Fix a number of text overflow issues in actions view and run list. Also
improve mobile view of run list.
Fixes: https://github.com/go-gitea/gitea/issues/30328
<img width="782" alt="Screenshot 2024-04-08 at 23 10 16"
src="3d9f9f88-3eab-44a0-8144-30c2b58b24cb">
<img width="935" alt="Screenshot 2024-04-08 at 23 17 46"
src="581d73ea-a31d-416b-be3a-47313b879b12">
<img width="1008" alt="Screenshot 2024-04-08 at 23 49 05"
src="c5d10565-f285-477f-8659-1caf94797647">
<img width="397" alt="Screenshot 2024-04-08 at 23 55 30"
src="368aaa75-1903-4058-9d75-d1fe91c564d6">
Fix the action issue in https://github.com/go-gitea/gitea/issues/30303,
specifically:
- Use opaque step header hover background to avoid transparency issue
- Un-sticky the `action-view-left` on mobile, it would otherwise overlap
into right view
- Improve commit summary, let it wrap
- Fix and comment z-indexes
- Tweak width for run-list-item-right so it wastes less space on desktop
- Synced latest changes to console colors from dark to light theme
<img width="467" alt="Screenshot 2024-04-06 at 18 58 15"
src="8ad26b72-6cd9-4522-8ad1-6fd86b2d0d53">
- switch from some weird status badge to label
- translate untranslated `Reset registration token` string
- change documentation link from act_runner README to Gitea Docs site
- fix "No runners available" message width
- use `ctx.Locale.Tr` where possible

This PR introduces a new UI element type for Gitea called `flex-item`.
It consists of a horizontal card with a leading, main and trailing part:

The idea behind it is that in Gitea UI, we have many cases where we use
this kind of layout, but it is achieved in many different ways:
- grid layout
- `.ui.list` with additional hacky flexbox
- `.ui.key.list` - looks to me like a style set originally created for
ssh/gpg key list, was used in many other places
- `.issue.list` - created for issue cards, used in many other places
- ...
This new style is based on `.issue.list`, specifically the refactoring
of it done in #25750.
In this PR, the new element is introduced and lots of templates are
being refactored to use that style. This allows to remove a lot of
page-specific css, makes many of the elements responsive or simply
provides a cleaner/better-looking way to present information.
A devtest section with the new style is also available.
<details>
<summary>Screenshots (left: before, right: after)</summary>



















</details>
---------
Co-authored-by: Giteabot <teabot@gitea.io>
Reorganize various CSS files for clarity, group together by subdirectory
in `index.css`. This reorders some of the rules, but I don't think it
should introduce any issues because of that.