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/admin/dashboard.tmpl

@@ -76,10 +76,7 @@
 		</h4>
 		{{/* TODO: make these stats work in multi-server deployments, likely needs per-server stats in DB */}}
 		<div class="ui attached table segment">
-			<div class="no-loading-indicator tw-hidden"></div>
-			<div hx-get="{{$.Link}}/system_status" hx-swap="morph:innerHTML" hx-trigger="every 5s" hx-indicator=".no-loading-indicator">
-				{{template "admin/system_status" .}}
-			</div>
+			{{template "admin/system_status" .}}
 		</div>
 	</div>
 {{template "admin/layout_footer" .}}

templates/admin/notice.tmpl

@@ -50,7 +50,7 @@
 										</div>
 									</div>
 								</div>
-								<button class="ui small button" id="delete-selection" data-link="{{.Link}}/delete" data-redirect="?page={{.Page.Paginater.Current}}">
+								<button class="ui small button" id="delete-selection" data-link="{{.Link}}/delete">
 									<span class="text">{{ctx.Locale.Tr "admin.notices.delete_selected"}}</span>
 								</button>
 							</th>

templates/admin/system_status.tmpl

@@ -1,4 +1,4 @@
-<dl class="admin-dl-horizontal">
+<dl class="admin-dl-horizontal" data-fetch-url="{{AppSubUrl}}/-/admin/system_status" data-fetch-sync="$morph" data-fetch-trigger="every 5s">
 	<dt>{{ctx.Locale.Tr "admin.dashboard.server_uptime"}}</dt>
 	<dd><relative-time format="duration" datetime="{{.SysStatus.StartTime}}">{{.SysStatus.StartTime}}</relative-time></dd>
 	<dt>{{ctx.Locale.Tr "admin.dashboard.current_goroutine"}}</dt>