Various UI fixes (#25264)

Numerous small UI fixes:

- Fix double border in collaborator list
- Fix system notice table background
- Mute links in repo and org lists
- Downsize projects edit buttons
- Improve milestones and project list rendering
- Condense milestone list entry to a single line of "metas"
- Mute ".." button in repo files list

templates/user/settings/repos.tmpl

@@ -23,8 +23,8 @@
 										{{else}}
 											<span class="icon">{{svg "octicon-repo"}}</span>
 										{{end}}
-										<a class="name" href="{{$repo.Link}}">{{$repo.OwnerName}}/{{$repo.Name}}</a>
-										<span>{{FileSize $repo.Size}}</span>
+										<a class="muted name" href="{{$repo.Link}}">{{$repo.OwnerName}}/{{$repo.Name}}</a>
+										<span class="text light-3">{{FileSize $repo.Size}}</span>
 										{{if $repo.IsFork}}
 											{{$.locale.Tr "repo.forked_from"}}
 											<span><a href="{{$repo.BaseRepo.Link}}">{{$repo.BaseRepo.OwnerName}}/{{$repo.BaseRepo.Name}}</a></span>