Dropdowns, Labels fixes and more CSS tweaks (#13733)

* Dropdowns and Labels fixes

- Rework dropdown, menu and label styles
- Improve issue sidebar milestone and label sections
- Fix archived repo and private org badge
- Move more colors to CSS vars
- Move issue number to end of title on issue page

* more dropdown fixes

* fix basic blue labels - fixes #13731

* improve class setting on svg

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/explore/repo_list.tmpl

@@ -8,7 +8,9 @@
 				<a class="name" href="{{.Link}}">
 					{{if or $.PageIsExplore $.PageIsProfileStarList }}{{if .Owner}}{{.Owner.Name}} / {{end}}{{end}}{{.Name}}
 				</a>
-				{{if .IsArchived}}<span class="ui compact label">{{$.i18n.Tr "repo.desc.archived"}}</span>{{end}}
+				{{if .IsArchived}}
+          <span class="ui basic label">{{$.i18n.Tr "repo.desc.archived"}}</span>
+        {{end}}
 				{{if .IsTemplate}}
 					{{if .IsPrivate}}
 						<span class="ui basic label">{{$.i18n.Tr "repo.desc.private_template"}}</span>