This PR implements a proposal to clean up the admin users table by
moving some information out to a separate user details page (which also
displays some additional information).
Other changes:
- move edit user page from `/admin/users/{id}` to
`/admin/users/{id}/edit` -> `/admin/users/{id}` now shows the user
details page
- show if user is instance administrator as a label instead of a
separate column
- separate explore users template into a page- and a shared one, to make
it possible to use it on the user details page
- fix issue where there was no margin between alert message and
following content on admin pages
<details>
<summary>Screenshots</summary>


</details>
Partially resolves#25939
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Co-authored-by: Giteabot <teabot@gitea.io>
Same as https://github.com/go-gitea/gitea/pull/26026 but for the user
settings page. It introduces a new `flex-container` class and shares it
across both pages.
Before and After:
<img width="1264" alt="Screenshot 2023-07-21 at 19 35 57"
src="1358dab4-55c0-40ce-a4d5-673099304f3d">
<img width="1269" alt="Screenshot 2023-07-21 at 19 35 42"
src="34812f6d-dc65-4009-b977-90e03efdc6d1">
This PR includes #26007 's changes but have a UI to prompt administrator
about the deprecated settings as well as the log or console warning.
Then users will have enough time to notice the problem and don't have
surprise like before.
<img width="1293" alt="图片"
src="c33355f0-1ea7-4fb3-ad43-cd23cd15391d">
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Reduce margins around admin boxes and reduce sidebar size from 275px to
240px. This is the same 16px margin we use on issue pages.
Before and After:
<img width="1270" alt="Screenshot 2023-07-21 at 00 28 11"
src="f9b0dcb0-8f7e-49b4-b130-54bf31c142fd">
<img width="1271" alt="Screenshot 2023-07-21 at 00 30 51"
src="ddd75d59-9ab9-4061-8989-852e89727560">