Remove polluted .ui.right (#26825)

Each change is tested manually line by line. There are too many changes
so I can't share dozens of screenshots.

In short:

1. `ui right` could be still used in `ui top attached header`, because
there is a special case.
2. A lot of `ui right` are just no-op, so they can be removed safely.
3. Some of the `ui right` should be replaced by `gt-float-right` (to
avoid breaking, leave them to the future).
4. A few of the `ui right` could be rewritten by flex.

templates/repo/issue/view_content/comments_delete_time.tmpl

@@ -1,7 +1,7 @@
 {{if .comment.Time}} {{/* compatibility with time comments made before v1.14 */}}
 	{{if (not .comment.Time.Deleted)}}
 		{{if (or .ctxData.IsAdmin (and .ctxData.IsSigned (eq .ctxData.SignedUserID .comment.PosterID)))}}
-			<span class="ui float right">
+			<span class="gt-float-right">
 				<div class="ui mini modal issue-delete-time-modal" data-id="{{.comment.Time.ID}}">
 					<form method="post" class="delete-time-form" action="{{.ctxData.RepoLink}}/issues/{{.ctxData.Issue.Index}}/times/{{.comment.TimeID}}/delete">
 						{{.ctxData.CsrfTokenHtml}}