Backport #27231 #27259 manually

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

I think it's better if the primary actions have primary color instead of
green which fits better into the overall single-color UI design. This PR
currently replaces every green button with primary:

<img width="141" alt="Screenshot 2023-09-16 at 14 07 59"
src="https://github.com/go-gitea/gitea/assets/115237/843c1e50-4fb2-4ec6-84ba-0efb9472dcbe">
<img width="161" alt="Screenshot 2023-09-16 at 14 07 51"
src="https://github.com/go-gitea/gitea/assets/115237/9442195a-a3b2-4a42-b262-8377d6f5c0d1">

Modal actions now use uncolored/primary instead of previous green/red
colors. I also removed the box-shadow on all basic buttons:

<img width="259" alt="Screenshot 2023-09-16 at 14 16 39"
src="https://github.com/go-gitea/gitea/assets/115237/5beea529-127a-44b0-8d4c-afa7b034a490">
<img width="261" alt="Screenshot 2023-09-16 at 14 17 42"
src="https://github.com/go-gitea/gitea/assets/115237/4757f7b2-4d46-49bc-a797-38bb28437b88">

The change currently includes the "Merge PR" button, for which we might
want to make an exception to match the icon color there:

<img width="442" alt="Screenshot 2023-09-16 at 14 33 53"
src="https://github.com/go-gitea/gitea/assets/115237/993ac1a5-c94d-4895-b76c-0d872181a70b">

Refactor some CSS styles and simplify code.

Some styles are not in use, remove them.

"inverted" class might not be needed because background of these two
buttons is light color.

inverted related rule from `semantic.css`:
```css
.ui.inverted.green.basic.buttons .button,
.ui.inverted.green.buttons .basic.button,
.ui.inverted.green.basic.button {
  background-color: transparent;
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.5) inset;
  color: #FFFFFF;
}
```

Before:
<img width="771" alt="截屏2023-04-10 17 21 22"
src="https://user-images.githubusercontent.com/17645053/230873878-cc64b3d6-ffa9-4cae-9280-07b06f7829b2.png">

After:
<img width="765" alt="截屏2023-04-10 17 22 14"
src="https://user-images.githubusercontent.com/17645053/230873956-9412054f-b739-4878-9ee9-57ff65eb7910.png">

The first step of the plan

* #23290

Thanks to @silverwind for the first try in #15394 . Close #10729 and a
lot of related issues.

The EasyMDE is not removed, now it works as a fallback, users can switch
between these two editors.

Editor list:

* Issue / PR comment
* Issue / PR comment edit
* Issue / PR comment quote reply
* PR diff view, inline comment
* PR diff view, inline comment edit
* PR diff view, inline comment quote reply
* Release editor
* Wiki editor

Some editors have attached dropzone

Screenshots:

<details>


![image](https://user-images.githubusercontent.com/2114189/229363558-7e44dcd4-fb6d-48a0-92f8-bd12f57bb0a0.png)


![image](https://user-images.githubusercontent.com/2114189/229363566-781489c8-5306-4347-9714-d71af5d5b0b1.png)


![image](https://user-images.githubusercontent.com/2114189/229363771-1717bf5c-0f2a-4fc2-ba84-4f5b2a343a11.png)


![image](https://user-images.githubusercontent.com/2114189/229363793-ad362d0f-a045-47bd-8f9d-05a9a842bb39.png)

</details>

---------

Co-authored-by: silverwind <me@silverwind.io>

HTML is not XML.

This improves a lot of accessibility shortcomings.
Every possible instance of `<div class="button">` matching the command
`ag '<[^ab].*?class=.*?[" ]button[ "]' templates/ | grep -v 'dropdown'`
has been converted when possible.
divs with the `dropdown` class and their children were omitted as
1. more analysis must be conducted whether the dropdowns still work as
intended when they are a `button` instead of a `div`.
2. most dropdowns have `div`s as children. The HTML standard disallows
`div`s inside `button`s.
3. When a dropdown child that's part of the displayed text content is
converted to a `button`, the dropdown can be focused twice

Further changes include that all "gitea-managed" buttons with JS code
received an `e.preventDefault()` so that they don't accidentally submit
an underlying form, which would execute instead of cancel the action.
Lastly, some minor issues were fixed as well during the refactoring.

## Future improvements

As mentioned in
https://github.com/go-gitea/gitea/pull/23337#discussion_r1127277391,
`<a>`s without `href` attribute are not focusable.
They should later on be converted to `<button>`s.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

Add a new "exclusive" option per label. This makes it so that when the
label is named `scope/name`, no other label with the same `scope/`
prefix can be set on an issue.

The scope is determined by the last occurence of `/`, so for example
`scope/alpha/name` and `scope/beta/name` are considered to be in
different scopes and can coexist.

Exclusive scopes are not enforced by any database rules, however they
are enforced when editing labels at the models level, automatically
removing any existing labels in the same scope when either attaching a
new label or replacing all labels.

In menus use a circle instead of checkbox to indicate they function as
radio buttons per scope. Issue filtering by label ensures that only a
single scoped label is selected at a time. Clicking with alt key can be
used to remove a scoped label, both when editing individual issues and
batch editing.

Label rendering refactor for consistency and code simplification:

* Labels now consistently have the same shape, emojis and tooltips
everywhere. This includes the label list and label assignment menus.
* In label list, show description below label same as label menus.
* Don't use exactly black/white text colors to look a bit nicer.
* Simplify text color computation. There is no point computing luminance
in linear color space, as this is a perceptual problem and sRGB is
closer to perceptually linear.
* Increase height of label assignment menus to show more labels. Showing
only 3-4 labels at a time leads to a lot of scrolling.
* Render all labels with a new RenderLabel template helper function.

Label creation and editing in multiline modal menu:

* Change label creation to open a modal menu like label editing.
* Change menu layout to place name, description and colors on separate
lines.
* Don't color cancel button red in label editing modal menu.
* Align text to the left in model menu for better readability and
consistent with settings layout elsewhere.

Custom exclusive scoped label rendering:

* Display scoped label prefix and suffix with slightly darker and
lighter background color respectively, and a slanted edge between them
similar to the `/` symbol.
* In menus exclusive labels are grouped with a divider line.

---------

Co-authored-by: Yarden Shoham <hrsi88@gmail.com>
Co-authored-by: Lauris BH <lauris@nix.lv>

* Refactor `i18n` to `locale`

- Currently we're using the `i18n` variable naming for the `locale`
struct. This contains locale's specific information and cannot be used
for general i18n purpose, therefore refactoring it to `locale` makes
more sense.
- Ref: https://github.com/go-gitea/gitea/pull/20096#discussion_r906699200

* Update routers/install/install.go

* make blue really blue

* replace blue button and label classes with primary

* add --color-blue-dark

* add light color variants, tweak a few colors

* fix colors

* add comment

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

* Add organization wide labels

Implement organization wide labels similar to organization wide
webhooks. This lets you create individual labels for organizations that can be used
for all repos under that organization (so being able to reuse the same
label across multiple repos).

This makes it possible for small organizations with many repos to use
labels effectively.

Fixes #7406

* Add migration

* remove comments

* fix tests

* Update options/locale/locale_en-US.ini

Removed unused translation string

* show org labels in issue search label filter

* Use more clear var name

* rename migration after merge from master

* comment typo

* update migration again after rebase with master

* check for orgID <=0 per guillep2k review

* fmt

* Apply suggestions from code review

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* remove unused code

* Make sure RepoID is 0 when searching orgID per code review

* more changes/code review requests

* More descriptive translation var per code review

* func description/delete comment when issue label deleted instead of hiding it

* remove comment

* only use issues in that repo when calculating number of open issues for org label on repo label page

* Add integration test for IssuesSearch API with labels

* remove unused function

* Update models/issue_label.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Use subquery in GetLabelIDsInReposByNames

* Fix tests to use correct orgID

* fix more tests

* IssuesSearch api now uses new BuildLabelNamesIssueIDsCondition. Add a few more tests as well

* update comment for clarity

* Revert previous code change now that we can use the new BuildLabelNamesIssueIDsCondition

* Don't sort repos by date in IssuesSearch API

After much debugging I've found a strange issue where in some cases MySQL will return a different result than other enigines if a query is sorted by a null collumn. For example with our integration test data where we don't set updated_unix in repository fixtures:

SELECT `id`, `owner_id`, `owner_name`, `lower_name`, `name`, `description`, `website`, `original_service_type`, `original_url`, `default_branch`, `num_watches`, `num_stars`, `num_forks`, `num_issues`, `num_closed_issues`, `num_pulls`, `num_closed_pulls`, `num_milestones`, `num_closed_milestones`, `is_private`, `is_empty`, `is_archived`, `is_mirror`, `status`, `is_fork`, `fork_id`, `is_template`, `template_id`, `size`, `is_fsck_enabled`, `close_issues_via_commit_in_any_branch`, `topics`, `avatar`, `created_unix`, `updated_unix` FROM `repository` ORDER BY updated_unix DESC LIMIT 15 OFFSET 45

Returns different results for MySQL than other engines. However, the similar query:

SELECT `id`, `owner_id`, `owner_name`, `lower_name`, `name`, `description`, `website`, `original_service_type`, `original_url`, `default_branch`, `num_watches`, `num_stars`, `num_forks`, `num_issues`, `num_closed_issues`, `num_pulls`, `num_closed_pulls`, `num_milestones`, `num_closed_milestones`, `is_private`, `is_empty`, `is_archived`, `is_mirror`, `status`, `is_fork`, `fork_id`, `is_template`, `template_id`, `size`, `is_fsck_enabled`, `close_issues_via_commit_in_any_branch`, `topics`, `avatar`, `created_unix`, `updated_unix` FROM `repository` ORDER BY updated_unix DESC LIMIT 15 OFFSET 30

Returns the same results.

This causes integration tests to fail on MySQL in certain cases but would never show up in a real installation. Since this API call always returns issues based on the optionally provided repo_priority_id or the issueID itself, there is no change to results by changing the repo sorting method used to get ids earlier in the function.

* linter is back!

* code review

* remove now unused option

* Fix newline at end of files

* more unused code

* update to master

* check for matching ids before query

* Update models/issue_label.go

Co-Authored-By: 6543 <6543@obermui.de>

* Update models/issue_label.go

* update comments

* Update routers/org/setting.go

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>
Co-authored-by: 6543 <6543@obermui.de>