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/projects/view.tmpl

@@ -108,7 +108,7 @@
 									>
 										{{svg "octicon-star"}} {{ctx.Locale.Tr "repo.projects.column.set_default"}}
 									</a>
-									<a class="item button link-action" data-url="{{$.Link}}/{{.ID}}" data-link-action-method="DELETE"
+									<a class="item button link-action" data-url="{{$.Link}}/{{.ID}}" data-fetch-method="DELETE"
 										data-modal-confirm-header="{{ctx.Locale.Tr "repo.projects.column.delete"}}"
 										data-modal-confirm-content="{{ctx.Locale.Tr "repo.projects.column.deletion_desc"}}"
 									>