Forbid jQuery .css and refactor all usage (#29852)

Tested all functionality. There is a [pre-existing
bug](https://github.com/go-gitea/gitea/issues/29853) when moving a
project panels which is not caused by this refactoring.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/features/repo-legacy.js

@@ -389,7 +389,7 @@ async function onEditContent(event) {
               dz.emit('complete', attachment);
               dz.files.push(attachment);
               fileUuidDict[attachment.uuid] = {submitted: true};
-              $dropzone.find(`img[src='${imgSrc}']`).css('max-width', '100%');
+              $dropzone.find(`img[src='${imgSrc}']`)[0].style.maxWidth = '100%';
               const $input = $(`<input id="${attachment.uuid}" name="files" type="hidden">`).val(attachment.uuid);
               $dropzone.find('.files').append($input);
             }