Replaces #10789
Convert the layout from flex-list helpers to a CSS-native grid. This allows to having buttons in different rows aligned to each other while keeping the layout responsive, i.e. looking good on both desktop and mobile.
### Preview (desktop)
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### Preview (mobile)
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### Preview (Guest)
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## Testing
Automated tests were added to make sure that actions in this list are still working, and for basic template logic. No tests were added for layout because layout being correct is an abstract concept that is difficult to explain to Playwright.
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11127
Reviewed-by: Antonin Delpeuch <wetneb@noreply.codeberg.org>