just a step towards  #25655

and some related refactoring

Related #14180
Related #25233 
Related #22639
Close #19786
Related #12763 

This PR will change all the branches retrieve method from reading git
data to read database to reduce git read operations.

- [x] Sync git branches information into database when push git data
- [x] Create a new table `Branch`, merge some columns of `DeletedBranch`
into `Branch` table and drop the table `DeletedBranch`.
- [x] Read `Branch` table when visit `code` -> `branch` page
- [x] Read `Branch` table when list branch names in `code` page dropdown
- [x] Read `Branch` table when list git ref compare page
- [x] Provide a button in admin page to manually sync all branches.
- [x] Sync branches if repository is not empty but database branches are
empty when visiting pages with branches list
- [x] Use `commit_time desc` as the default FindBranch order by to keep
consistent as before and deleted branches will be always at the end.

---------

Co-authored-by: Jason Song <i@wolfogre.com>

Refactor `modules/indexer` to make it more maintainable. And it can be
easier to support more features. I'm trying to solve some of issue
searching, this is a precursor to making functional changes.

Current supported engines and the index versions:

| engines | issues | code |
| - | - | - |
| db | Just a wrapper for database queries, doesn't need version | - |
| bleve | The version of index is **2** | The version of index is **6**
|
| elasticsearch | The old index has no version, will be treated as
version **0** in this PR | The version of index is **1** |
| meilisearch | The old index has no version, will be treated as version
**0** in this PR | - |


## Changes

### Split

Splited it into mutiple packages

```text
indexer
├── internal
│   ├── bleve
│   ├── db
│   ├── elasticsearch
│   └── meilisearch
├── code
│   ├── bleve
│   ├── elasticsearch
│   └── internal
└── issues
    ├── bleve
    ├── db
    ├── elasticsearch
    ├── internal
    └── meilisearch
```

- `indexer/interanal`: Internal shared package for indexer.
- `indexer/interanal/[engine]`: Internal shared package for each engine
(bleve/db/elasticsearch/meilisearch).
- `indexer/code`: Implementations for code indexer.
- `indexer/code/internal`: Internal shared package for code indexer.
- `indexer/code/[engine]`: Implementation via each engine for code
indexer.
- `indexer/issues`: Implementations for issues indexer.

### Deduplication

- Combine `Init/Ping/Close` for code indexer and issues indexer.
- ~Combine `issues.indexerHolder` and `code.wrappedIndexer` to
`internal.IndexHolder`.~ Remove it, use dummy indexer instead when the
indexer is not ready.
- Duplicate two copies of creating ES clients.
- Duplicate two copies of `indexerID()`.


### Enhancement

- [x] Support index version for elasticsearch issues indexer, the old
index without version will be treated as version 0.
- [x] Fix spell of `elastic_search/ElasticSearch`, it should be
`Elasticsearch`.
- [x] Improve versioning of ES index. We don't need `Aliases`:
- Gitea does't need aliases for "Zero Downtime" because it never delete
old indexes.
- The old code of issues indexer uses the orignal name to create issue
index, so it's tricky to convert it to an alias.
- [x] Support index version for meilisearch issues indexer, the old
index without version will be treated as version 0.
- [x] Do "ping" only when `Ping` has been called, don't ping
periodically and cache the status.
- [x] Support the context parameter whenever possible.
- [x] Fix outdated example config.
- [x] Give up the requeue logic of issues indexer: When indexing fails,
call Ping to check if it was caused by the engine being unavailable, and
only requeue the task if the engine is unavailable.
- It is fragile and tricky, could cause data losing (It did happen when
I was doing some tests for this PR). And it works for ES only.
- Just always requeue the failed task, if it caused by bad data, it's a
bug of Gitea which should be fixed.

---------

Co-authored-by: Giteabot <teabot@gitea.io>

Replace #16455

Close #21803

Mixing different Gitea contexts together causes some problems:

1. Unable to respond proper content when error occurs, eg: Web should
respond HTML while API should respond JSON
2. Unclear dependency, eg: it's unclear when Context is used in
APIContext, which fields should be initialized, which methods are
necessary.


To make things clear, this PR introduces a Base context, it only
provides basic Req/Resp/Data features.

This PR mainly moves code. There are still many legacy problems and
TODOs in code, leave unrelated changes to future PRs.

The "mirror" table and "repository" table might be out-of-sync in some
cases.

It means that "IsMirror=true" but "Mirror=nil"

This PR removes unnecessary "Mirror" field, rename "Mirror" to
"PullMirror" and fix nil panic bug.


Screenshot of changed templates:


![image](https://github.com/go-gitea/gitea/assets/2114189/c0f2bdfc-5911-43ea-b989-b19619de4235)



![image](https://github.com/go-gitea/gitea/assets/2114189/1078b41a-484f-4c06-8c2f-edb9e658275d)

fix #12192 Support SSH for go get

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>
Co-authored-by: mfk <mfk@hengwei.com.cn>
Co-authored-by: silverwind <me@silverwind.io>

1. Remove unused fields/methods in web context.
2. Make callers call target function directly instead of the light
wrapper like "IsUserRepoReaderSpecific"
3. The "issue template" code shouldn't be put in the "modules/context"
package, so move them to the service package.

---------

Co-authored-by: Giteabot <teabot@gitea.io>

The "modules/context.go" is too large to maintain.

This PR splits it to separate files, eg: context_request.go,
context_response.go, context_serve.go

This PR will help:

1. The future refactoring for Gitea's web context (eg: simplify the context)
2. Introduce proper "range request" support
3. Introduce context function

This PR only moves code, doesn't change any logic.

Due to #24409 , we can now specify '--not' when getting all commits from
a repo to exclude commits from a different branch.

When I wrote that PR, I forgot to also update the code that counts the
number of commits in the repo. So now, if the --not option is used, it
may return too many commits, which can indicate that another page of
data is available when it is not.

This PR passes --not to the commands that count the number of commits in
a repo

The `SHOW_FOOTER_BRANDING` came from year 2015, and it seems nobody ever
uses it. It only shows an GitHub icon which seems unrelated to Gitea, it
doesn't do what document says. So, remove it.

## :warning: Breaking

Users can now remove the key `[other].SHOW_FOOTER_BRANDING` from their
app.ini.

![image](https://user-images.githubusercontent.com/2114189/232561612-2bfcfd0a-fc04-47ba-965f-5d0bcea46c54.png)

Previously, not all repo tabs had shown the RSS icon in the repo header
because the context data was not being set. Added this context data in a
new function.

Before:

<img width="806" alt="image"
src="https://user-images.githubusercontent.com/115237/229639615-9cc00e75-3a26-4ff4-a6f2-316c1fccc596.png">

After:

<img width="815" alt="Screenshot 2023-04-04 at 00 16 17"
src="https://user-images.githubusercontent.com/115237/229639201-2e1c015b-1f13-46d4-aa14-e7a82fab3982.png">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

The _graceful_ should fail less when the `.editorconfig` file isn't
properly written, e.g. boolean values from YAML or unparseable numbers
(when a number is expected). As is... information is lost as the
_warning_ (a go-multierror.Error) is ignored. If anybody knows how to
send them to the UI as warning; any help is appreciated.

Closes #20694

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

Closes #20955

This PR adds the possibility to disable blank Issues, when the Repo has
templates. This can be done by creating the file
`.gitea/issue_config.yaml` with the content `blank_issues_enabled` in
the Repo.

This PR fixes the tags sort issue mentioned in #23432
The tags on dropdown shoud be sorted in descending order of time but are
not. Because when getting tags, it execeutes `git tag sort
--sort=-taggerdate`. Git supports two types of tags: lightweight and
annotated, and `git tag sort --sort=-taggerdate` dosen't work with
lightweight tags, which will not give correct result. This PR add
`GetTagNamesByRepoID ` to get tags from the database so the tags are
sorted.

Also adapt this change to the droplist when comparing branches. 

Dropdown places:

<img width="369" alt="截屏2023-03-15 14 25 39"
src="https://user-images.githubusercontent.com/17645053/225224506-65a72e50-4c11-41d7-8187-a7e9c7dab2cb.png">

<img width="675" alt="截屏2023-03-15 14 25 27"
src="https://user-images.githubusercontent.com/17645053/225224526-65ce8008-340c-43f6-aa65-b6bd9e1a1bf1.png">

Fixes https://github.com/go-gitea/gitea/issues/22963

---------

Co-authored-by: Yarden Shoham <hrsi88@gmail.com>

In Go code, HTMLURL should be only used for external systems, like
API/webhook/mail/notification, etc.

If a URL is used by `Redirect` or rendered in a template, it should be a
relative URL (aka `Link()` in Gitea)

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

Close #13539.

Co-authored by: @lunny @appleboy @fuxiaohei and others.

Related projects:
- https://gitea.com/gitea/actions-proto-def
- https://gitea.com/gitea/actions-proto-go
- https://gitea.com/gitea/act
- https://gitea.com/gitea/act_runner

### Summary

The target of this PR is to bring a basic implementation of "Actions",
an internal CI/CD system of Gitea. That means even though it has been
merged, the state of the feature is **EXPERIMENTAL**, and please note
that:

- It is disabled by default;
- It shouldn't be used in a production environment currently;
- It shouldn't be used in a public Gitea instance currently;
- Breaking changes may be made before it's stable.

**Please comment on #13539 if you have any different product design
ideas**, all decisions reached there will be adopted here. But in this
PR, we don't talk about **naming, feature-creep or alternatives**.

### ⚠️ Breaking

`gitea-actions` will become a reserved user name. If a user with the
name already exists in the database, it is recommended to rename it.

### Some important reviews

- What is `DEFAULT_ACTIONS_URL` in `app.ini` for?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1055954954
- Why the api for runners is not under the normal `/api/v1` prefix?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1061173592
- Why DBFS?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1061301178
- Why ignore events triggered by `gitea-actions` bot?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1063254103
- Why there's no permission control for actions?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1090229868

### What it looks like

<details>

#### Manage runners

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205870657-c72f590e-2e08-4cd4-be7f-2e0abb299bbf.png">

#### List runs

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205872794-50fde990-2b45-48c1-a178-908e4ec5b627.png">


#### View logs

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205872501-9b7b9000-9542-4991-8f55-18ccdada77c3.png">



</details>

### How to try it

<details>

#### 1. Start Gitea

Clone this branch and [install from
source](https://docs.gitea.io/en-us/install-from-source).

Add additional configurations in `app.ini` to enable Actions:

```ini
[actions]
ENABLED = true
```

Start it.

If all is well, you'll see the management page of runners:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205877365-8e30a780-9b10-4154-b3e8-ee6c3cb35a59.png">


#### 2. Start runner

Clone the [act_runner](https://gitea.com/gitea/act_runner), and follow
the
[README](https://gitea.com/gitea/act_runner/src/branch/main/README.md)
to start it.

If all is well, you'll see a new runner has been added:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205878000-216f5937-e696-470d-b66c-8473987d91c3.png">

#### 3. Enable actions for a repo

Create a new repo or open an existing one, check the `Actions` checkbox
in settings and submit.

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205879705-53e09208-73c0-4b3e-a123-2dcf9aba4b9c.png">
<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205879383-23f3d08f-1a85-41dd-a8b3-54e2ee6453e8.png">

If all is well, you'll see a new tab "Actions":

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205881648-a8072d8c-5803-4d76-b8a8-9b2fb49516c1.png">

#### 4. Upload workflow files

Upload some workflow files to `.gitea/workflows/xxx.yaml`, you can
follow the [quickstart](https://docs.github.com/en/actions/quickstart)
of GitHub Actions. Yes, Gitea Actions is compatible with GitHub Actions
in most cases, you can use the same demo:

```yaml
name: GitHub Actions Demo
run-name: ${{ github.actor }} is testing out GitHub Actions 🚀
on: [push]
jobs:
  Explore-GitHub-Actions:
    runs-on: ubuntu-latest
    steps:
      - run: echo "🎉 The job was automatically triggered by a ${{ github.event_name }} event."
      - run: echo "🐧 This job is now running on a ${{ runner.os }} server hosted by GitHub!"
      - run: echo "🔎 The name of your branch is ${{ github.ref }} and your repository is ${{ github.repository }}."
      - name: Check out repository code
        uses: actions/checkout@v3
      - run: echo "💡 The ${{ github.repository }} repository has been cloned to the runner."
      - run: echo "🖥️ The workflow is now ready to test your code on the runner."
      - name: List files in the repository
        run: |
          ls ${{ github.workspace }}
      - run: echo "🍏 This job's status is ${{ job.status }}."
```

If all is well, you'll see a new run in `Actions` tab:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205884473-79a874bc-171b-4aaf-acd5-0241a45c3b53.png">

#### 5. Check the logs of jobs

Click a run and you'll see the logs:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205884800-994b0374-67f7-48ff-be9a-4c53f3141547.png">

#### 6. Go on

You can try more examples in [the
documents](https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions)
of GitHub Actions, then you might find a lot of bugs.

Come on, PRs are welcome.

</details>

See also: [Feature Preview: Gitea
Actions](https://blog.gitea.io/2022/12/feature-preview-gitea-actions/)

---------

Co-authored-by: a101211279 <1012112796@qq.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: ChristopherHX <christopher.homberger@web.de>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

This PR introduce glob match for protected branch name. The separator is
`/` and you can use `*` matching non-separator chars and use `**` across
separator.

It also supports input an exist or non-exist branch name as matching
condition and branch name condition has high priority than glob rule.

Should fix #2529 and #15705

screenshots

<img width="1160" alt="image"
src="https://user-images.githubusercontent.com/81045/205651179-ebb5492a-4ade-4bb4-a13c-965e8c927063.png">

Co-authored-by: zeripath <art27@cantab.net>

After #22362, we can feel free to use transactions without
`db.DefaultContext`.

And there are still lots of models using `db.DefaultContext`, I think we
should refactor them carefully and one by one.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

Fix #13485.

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: Lauris BH <lauris@nix.lv>

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

Fix #20456

At some point during the 1.17 cycle abbreviated refishs to issue
branches started breaking. This is likely due serious inconsistencies in
our management of refs throughout Gitea - which is a bug needing to be
addressed in a different PR. (Likely more than one)

We should try to use non-abbreviated `fullref`s as much as possible.
That is where a user has inputted a abbreviated `refish` we should add
`refs/heads/` if it is `branch` etc. I know people keep writing and
merging PRs that remove prefixes from stored content but it is just
wrong and it keeps causing problems like this. We should only remove the
prefix at the time of
presentation as the prefix is the only way of knowing umambiguously and
permanently if the `ref` is referring to a `branch`, `tag` or `commit` /
`SHA`. We need to make it so that every ref has the appropriate prefix,
and probably also need to come up with some definitely unambiguous way
of storing `SHA`s if they're used in a `ref` or `refish` field. We must
not store a potentially
ambiguous `refish` as a `ref`. (Especially when referring a `tag` -
there is no reason why users cannot create a `branch` with the same
short name as a `tag` and vice versa and any attempt to prevent this
will fail. You can even create a `branch` and a
`tag` that matches the `SHA` pattern.)

To that end in order to fix this bug, when parsing issue templates check
the provided `Ref` (here a `refish` because almost all users do not know
or understand the subtly), if it does not start with `refs/` add the
`BranchPrefix` to it. This allows people to make their templates refer
to a `tag` but not to a `SHA` directly. (I don't think that is
particularly unreasonable but if people disagree I can make the `refish`
be checked to see if it matches the `SHA` pattern.)

Next we need to handle the issue links that are already written. The
links here are created with `git.RefURL`

Here we see there is a bug introduced in #17551 whereby the provided
`ref` argument can be double-escaped so we remove the incorrect external
escape. (The escape added in #17551 is in the right place -
unfortunately I missed that the calling function was doing the wrong
thing.)

Then within `RefURL()` we check if an unprefixed `ref` (therefore
potentially a `refish`) matches the `SHA` pattern before assuming that
is actually a `commit` - otherwise is assumed to be a `branch`. This
will handle most of the problem cases excepting the very unusual cases
where someone has deliberately written a `branch` to look like a `SHA1`.

But please if something is called a `ref` or interpreted as a `ref` make
it a full-ref before storing or using it. By all means if something is a
`branch` assume the prefix is removed but always add it back in if you
are using it as a `ref`. Stop storing abbreviated `branch` names and
`tag` names - which are `refish` as a `ref`. It will keep on causing
problems like this.

Fix #20456

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

This patch provide a mechanism to disable RSS/Atom feed.

Signed-off-by: Xinyu Zhou <i@sourcehut.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

Fixes #17655

If you rename `user1` to `user2` and visit `/user1` you get redirected
to `/user2`. But if you visit `/user1/repo` you just get a 404 error.
With this PR the user is redirected to `/user2/repo`.

Before, a tag for a draft release disappeared in the tag list, fix #21262.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

* feat: extend issue template for yaml

* feat: support yaml template

* feat: render form to markdown

* feat: support yaml template for pr

* chore: rename to Fields

* feat: template unmarshal

* feat: split template

* feat: render to markdown

* feat: use full name as template file name

* chore: remove useless file

* feat: use dropdown of fomantic ui

* feat: update input style

* docs: more comments

* fix: render text without render

* chore: fix lint error

* fix: support use description as about in markdown

* fix: add field class in form

* chore: generate swagger

* feat: validate template

* feat: support is_nummber and regex

* test: fix broken unit tests

* fix: ignore empty body of md template

* fix: make multiple easymde editors work in one page

* feat: better UI

* fix: js error in pr form

* chore: generate swagger

* feat: support regex validation

* chore: generate swagger

* fix: refresh each markdown editor

* chore: give up required validation

* fix: correct issue template candidates

* fix: correct checkboxes style

* chore: ignore .hugo_build.lock in docs

* docs: separate out a new doc for merge templates

* docs: introduce syntax of yaml template

* feat: show a alert for invalid templates

* test: add case for a valid template

* fix: correct attributes of required checkbox

* fix: add class not-under-easymde for dropzone

* fix: use more back-quotes

* chore: remove translation in zh-CN

* fix EasyMDE statusbar margin

* fix: remove repeated blocks

* fix: reuse regex for quotes

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

* Move some files into models' sub packages

* Move functions

* merge main branch

* Fix check

* fix check

* Fix some tests

* Fix lint

* Fix lint

* Revert lint changes

* Fix error comments

* Fix lint

Co-authored-by: 6543 <6543@obermui.de>

- Add a new push mirror to specific repository
- Sync now ( send all the changes to the configured push mirrors )
- Get list of all push mirrors of a repository
- Get a push mirror by ID
- Delete push mirror by ID

Signed-off-by: Mohamed Sekour <mohamed.sekour@exfo.com>
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: zeripath <art27@cantab.net>

The LastCommitCache code is a little complex and there is unnecessary
duplication between the gogit and nogogit variants.

This PR adds the LastCommitCache as a field to the git.Repository and
pre-creates it in the ReferencesGit helpers etc. There has been some
simplification and unification of the variant code.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

Fixes #19979

* Fix mirror template bug

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

* Move access and repo permission to models/perm/access

* fix test

* fix git test

* Move functions sequence

* Some improvements per @KN4CK3R and @delvh

* Move issues related code to models/issues

* Move some issues related sub package

* Merge

* Fix test

* Fix test

* Fix test

* Fix test

* Rename some files

* Move access and repo permission to models/perm/access

* fix test

* Move some git related files into sub package models/git

* Fix build

* fix git test

* move lfs to sub package

* move more git related functions to models/git

* Move functions sequence

* Some improvements per @KN4CK3R and @delvh

* Move some repository related code into sub package

* Move more repository functions out of models

* Fix lint

* Some performance optimization for webhooks and others

* some refactors

* Fix lint

* Fix

* Update modules/repository/delete.go

Co-authored-by: delvh <dev.lh@web.de>

* Fix test

* Merge

* Fix test

* Fix test

* Fix test

* Fix test

Co-authored-by: delvh <dev.lh@web.de>

A `repo_model.Mirror` repository field (`.Repo`) will not automatically
be set, but is used without checking in mirror_pull.go:UpdateAddress.
This will cause an NPE.

This PR changes UpdateAddress to use the helper function GetRepository()
helping prevent future NPEs but also changes modules/context/repo.go to
ensure that the Mirror.Repo is set.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Move almost all functions' parameter db.Engine to context.Context
* remove some unnecessary wrap functions

* Move access and repo permission to models/perm/access

* Remove unnecessary code

* Only check for non-finished migrating task

- Only check if a non-finished migrating task exists for a mirror before
fetching the mirror details from the database.
- Resolves #19600
- Regression: #19588

* Clarify function

- When a repository is still being migrated, don't try to fetch the
Mirror from the database. Instead skip it. This allows to visit
repositories that are still being migrated and were configured to be
mirrored.
- Resolves #19585
- Regression: #19295

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Adds a feature [like GitHub has](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request-from-a-fork) (step 7).
If you create a new PR from a forked repo, you can select (and change later, but only if you are the PR creator/poster) the "Allow edits from maintainers" option.
Then users with write access to the base branch get more permissions on this branch:
* use the update pull request button
* push directly from the command line (`git push`)
* edit/delete/upload files via web UI
* use related API endpoints

You can't merge PRs to this branch with this enabled, you'll need "full" code write permissions.

This feature has a pretty big impact on the permission system. I might forgot changing some things or didn't find security vulnerabilities. In this case, please leave a review or comment on this PR.

Closes #17728

Co-authored-by: 6543 <6543@obermui.de>

make more usage of context, to have more db transaction in one session

(make diff of  #9307 smaller)

* check if GitRepo already open and close if

* only run RepoAssignment once

* refactor context helper for api to open GitRepo

The main purpose is to refactor the legacy `unknwon/com` package.
1. Remove most imports of `unknwon/com`, only `util/legacy.go` imports the legacy `unknwon/com`
2. Use golangci's depguard to process denied packages
3. Fix some incorrect values in golangci.yml, eg, the version should be quoted string `"1.18"`
4. Use correctly escaped content for `go-import` and `go-source` meta tags
5. Refactor `com.Expand` to our stable (and the same fast) `vars.Expand`, our `vars.Expand` can still return partially rendered content even if the template is not good (eg: key mistach).

* OpenRepositoryCtx -> OpenRepository
* OpenRepository -> openRepositoryWithDefaultContext, only for internal usage