Improve queue & process & stacktrace (#24636)

Although some features are mixed together in this PR, this PR is not
that large, and these features are all related.

Actually there are more than 70 lines are for a toy "test queue", so
this PR is quite simple.

Major features:

1. Allow site admin to clear a queue (remove all items in a queue)
* Because there is no transaction, the "unique queue" could be corrupted
in rare cases, that's unfixable.
* eg: the item is in the "set" but not in the "list", so the item would
never be able to be pushed into the queue.
* Now site admin could simply clear the queue, then everything becomes
correct, the lost items could be re-pushed into queue by future
operations.
3. Split the "admin/monitor" to separate pages
4. Allow to download diagnosis report
* In history, there were many users reporting that Gitea queue gets
stuck, or Gitea's CPU is 100%
    * With diagnosis report, maintainers could know what happens clearly

The diagnosis report sample:
[gitea-diagnosis-20230510-192913.zip](https://github.com/go-gitea/gitea/files/11441346/gitea-diagnosis-20230510-192913.zip)
, use "go tool pprof profile.dat" to view the report.


Screenshots:


![image](https://github.com/go-gitea/gitea/assets/2114189/320659b4-2eda-4def-8dc0-5ea08d578063)


![image](https://github.com/go-gitea/gitea/assets/2114189/c5c46fae-9dc0-44ca-8cd3-57beedc5035e)


![image](https://github.com/go-gitea/gitea/assets/2114189/6168a811-42a1-4e64-a263-0617a6c8c4fe)

---------

Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: Giteabot <teabot@gitea.io>

templates/admin/queue_manage.tmpl

@@ -22,7 +22,18 @@
 						<td>{{.Queue.GetItemTypeName}}</td>
 						<td>{{$sum := .Queue.GetWorkerNumber}}{{if lt $sum 0}}-{{else}}{{$sum}}{{end}}</td>
 						<td>{{if lt $sum 0}}-{{else}}{{.Queue.GetWorkerMaxNumber}}{{end}}</td>
-						<td>{{$sum = .Queue.GetQueueItemNumber}}{{if lt $sum 0}}-{{else}}{{$sum}}{{end}}</td>
+						<td>
+							{{$sum = .Queue.GetQueueItemNumber}}
+							{{if lt $sum 0}}
+								-
+							{{else}}
+								{{$sum}}
+								<form action="{{$.Link}}/remove-all-items" method="post" class="gt-dib gt-ml-4">
+									{{$.CsrfTokenHtml}}
+									<button class="ui tiny basic red button">{{.locale.Tr "admin.monitor.queue.settings.remove_all_items"}}</button>
+								</form>
+							{{end}}
+						</td>
 					</tr>
 				</tbody>
 			</table>