Add label/author/assignee filters to the user/org home issue list (#32779)

Replace #26661, fix #25979

Not perfect, but usable and much better than before. Since it is quite
complex, I am not quite sure whether there would be any regression, if
any, I will fix in first time.

I have tested the related pages many times: issue list, milestone issue
list, project view, user issue list, org issue list.

templates/repo/issue/milestone/filter_list.tmpl

@@ -1,5 +1,5 @@
 <!-- Sort -->
-<div class="list-header-sort ui small dropdown type jump item">
+<div class="item ui small dropdown jump">
 	<span class="text">
 		{{ctx.Locale.Tr "repo.issues.filter_sort"}}
 	</span>