Backport #27323 by @wxiaoguang
Fix#27313 (see the comment)
And some UI improvements:
### Before


### After



Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Close#27012
By the way, rename the single-word ID to a long ID.


1. Fine tune the CSS styles, and add more examples
2. Add necessary "dimmer" animation for modal dialogs, otherwise the UI
seems flicking (follow #26469)
- The label text color on project board is not contrasting enough,
changed to colors that are same as places that also used
`useLightTextOnBackground` function
([util_render.go](2cdf260f42/modules/templates/util_render.go (L136-L141)),
[Context
Popup](2cdf260f42/web_src/js/components/ContextPopup.vue (L81-L84)))
- background of modal `content` is `#ffffff` (from fomantic) right now,
which does not look good on dark mode, so changed to `var(--color-body)`
Before:
<img width="1378" alt="Screen Shot 2023-06-21 at 14 24 13"
src="1527ca28-c884-4ca9-a4be-7a72ad1a093a">
<img width="900" alt="Screen Shot 2023-06-21 at 14 25 52"
src="fab82116-7376-4027-a0a4-9eedf9fb0a30">
After:
<img width="1383" alt="Screen Shot 2023-06-21 at 14 19 33"
src="fe0997e7-fee6-4522-bc4e-545088ec1cc8">
<img width="797" alt="Screen Shot 2023-06-21 at 14 32 42"
src="b0591af0-950c-4448-9430-34d6c7215971">
Co-Author: @wxiaoguang
It is more convenient that user just need to enter a new branch name after he selects the branch which he want to rename.
So this PR move the function of renaming branch to the page of branches list.
This PR also restyle the button of `new branch`, `download`, `delete`....
https://user-images.githubusercontent.com/33891828/235277997-413060bb-759f-430a-b5c4-df5e40ffcd28.mov
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>