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>

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>

* Move some helper files out of models

* Some improvements

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

Use DeployKeyID to replace the IsDeployKey, then CanWriteCode uses the DeployKeyID to check the write permission.

* Some refactors related repository model

* Move more methods out of repository

* Move repository into models/repo

* Fix test

* Fix test

* some improvements

* Remove unnecessary function

* Move user related model into models/user

* Fix lint for windows

* Fix windows lint

* Fix windows lint

* Move some tests in models

* Merge

* chore: rewrite format.

* chore: update format

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* chore: update format

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* chore: Adjacent parameters with the same type should be grouped together

* chore: update format.

* Set setting.AppURL as GITEA_ROOT_URL environment variable during pushes

Fix #11738

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

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

* Move PushUpdateAddDeleteTags to repository module from models

* Fix deadlock on sqlite

* Add owner_name column for table repository for maintaince reason

* refactor

* Fix tests

* fix test

* fix bug when fork repository

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

#8982 attempted to enforce the gitea environment for pushes - unfortunately it tested the settings before they were actually read in - and therefore does not do that!

* fix bug create/edit wiki pages when code master branch protected

* improve FullPushingEnvironment function

* Fix #6946 by checking PullRequest ID on pushing

* Ensure we have the owner name, the pr attributes and the the issue

* Fix TestSearchRepo by waiting till indexing is done

* Update integrations/repo_search_test.go

* changes as per @mrsdizzie

* missing comma

* Spelling mistake

* Fix full pushing environment

* Move hook functionality internally

* Internalise serv logic

* Remove old internal paths

* finally remove the gitlogger

* Disallow push on archived repositories

* fix lint error

* Update modules/private/key.go

* Update routers/private/hook.go

* Update routers/private/hook.go

* Update routers/private/hook.go

* Updated routers/private/serv.go

* Fix LFS Locks over SSH

* rev-list needs to be run by the hook process

* fixup

* Improve git test

* Ensure that the lfs files are created with a different prefix

* Reduce the replication in git_test.go

* slight refactor

* Remove unnecessary "/"

* Restore ensureAnonymousClone

* Restore ensureAnonymousClone

* Run rev-list on server side

* Try passing in the alternative directories instead

* Mark test as skipped

* Improve git test

* Ensure that the lfs files are created with a different prefix
* Reduce the replication in git_test.go
* Remove unnecessary "/"

* Stop running hooks on pr merge

* Remove SSH_ORIGINAL_COMMAND from the pushing environment

* Add options to git.Clone to make it more capable

* Begin the process of removing the local copy and tidy up

* Remove Wiki LocalCopy Checkouts

* Remove the last LocalRepo helpers

* Remove WithTemporaryFile

* Enable push-hooks for these routes

* Ensure tests cope with hooks

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

* Remove Repository.LocalCopyPath()

* Move temporary repo to use the standard temporary path

* Fix the tests

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

* Remove LocalWikiPath

* Fix missing remove

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

* Use AppURL for Oauth user link (#6894)

* Use AppURL for Oauth user link

Fix #6843

* Update oauth.go

* Update oauth.go

* internal/ssh: ignore env command totally (#6825)

* ssh: ignore env command totally

* Remove commented code 

Needed fix described in issue #6889

* Escape the commit message on issues update and title in telegram hook (#6901)

* update sdk to latest (#6903)

* improve description of branch protection (fix #6886) (#6906)

The branch protection description text were not quite accurate.

* Fix logging documentation (#6904)

* ENABLE_MACARON_REDIRECT should be REDIRECT_MACARON_LOG

* Allow DISABLE_ROUTER_LOG to be set in the [log] section

* [skip ci] Updated translations via Crowdin

* Move sdk structs to modules/structs (#6905)

* move sdk structs to moduels/structs

* fix tests

* fix fmt

* fix swagger

* fix vendor