Fix and clean up ConfirmModal (#31283)

Bug: orange button color was removed in
https://github.com/go-gitea/gitea/pull/30475, replaced with red
Bug: translation text was not html-escaped
Refactor: Replaced as much jQuery as possible, added useful
`createElementFromHTML`
Refactor: Remove colors checks that don't exist on `.link-action`

<img width="381" alt="image"
src="5900bf6a-8a86-4a86-b368-0559cbfea66e">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

web_src/js/features/repo-issue-list.js

@@ -76,7 +76,7 @@ function initRepoIssueListCheckboxes() {
     // for delete
     if (action === 'delete') {
       const confirmText = e.target.getAttribute('data-action-delete-confirm');
-      if (!await confirmModal({content: confirmText, buttonColor: 'orange'})) {
+      if (!await confirmModal(confirmText, {confirmButtonColor: 'red'})) {
         return;
       }
     }