Refactor htmx and fetch-action related code (#37186)

This is the first step (the hardest part):

* repo file list last commit message lazy load
* admin server status monitor
* watch/unwatch (normal page, watchers page)
* star/unstar (normal page, watchers page)
* project view, delete column
* workflow dispatch, switch the branch
* commit page: load branches and tags referencing this commit

The legacy "data-redirect" attribute is removed, it only makes the page
reload (sometimes using an incorrect link).

Also did cleanup for some devtest pages.

templates/repo/view_list.tmpl

@@ -1,5 +1,11 @@
 {{/* use grid layout, still use the old ID because there are many other CSS styles depending on this ID */}}
-<div id="repo-files-table" {{if .HasFilesWithoutLatestCommit}}hx-indicator="#repo-files-table .repo-file-cell.message" hx-trigger="load" hx-swap="morph" hx-post="{{.LastCommitLoaderURL}}"{{end}}>
+<div id="repo-files-table"
+	{{if .HasFilesWithoutLatestCommit}}
+		data-fetch-url="{{.LastCommitLoaderURL}}"
+		data-fetch-trigger="load" data-fetch-sync="$morph"
+		data-fetch-indicator="#repo-files-table .repo-file-cell.notready.message"
+	{{end}}
+>
 	<div class="repo-file-line repo-file-last-commit">
 		{{template "repo/latest_commit" .}}
 		<div>{{if and .LatestCommit .LatestCommit.Committer}}{{DateUtils.TimeSince .LatestCommit.Committer.When}}{{end}}</div>
@@ -15,7 +21,7 @@
 			{{$entry := $item.Entry}}
 			{{$commit := $item.Commit}}
 			{{$submoduleFile := $item.SubmoduleFile}}
-			<div class="repo-file-cell name muted-links {{if not $commit}}notready{{end}}">
+			<div class="repo-file-cell name muted-links">
 				{{index $.FileIcons $entry.Name}}
 				{{if $entry.IsSubModule}}
 					{{$submoduleLink := $submoduleFile.SubmoduleWebLinkTree ctx}}
@@ -47,7 +53,7 @@
 					{{end}}
 				{{end}}
 			</div>
-			<div class="repo-file-cell message commit-summary loading-icon-2px">
+			<div class="repo-file-cell message commit-summary {{if not $commit}}notready{{end}}">
 				{{if $commit}}
 					{{$commitLink := printf "%s/commit/%s" $.RepoLink (PathEscape $commit.ID.String)}}
 					{{ctx.RenderUtils.RenderCommitMessageLinkSubject $commit.Message $commitLink $.Repository}}