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/issue/view_content/update_branch_by_merge.tmpl

@@ -9,7 +9,7 @@
 			{{if and $.UpdateAllowed $.UpdateByRebaseAllowed}}
 				<div class="tw-inline-block">
 					<div id="update-pr-branch-with-base" class="ui buttons">
-						<button class="ui button" data-do="{{$.Issue.Link}}/update" data-redirect="{{$.Issue.Link}}">
+						<button class="ui button" data-do="{{$.Issue.Link}}/update">
 							<span class="button-text">
 								{{ctx.Locale.Tr "repo.pulls.update_branch"}}
 							</span>