Drag-and-drop improvements for projects and issue pins (#29875)

1. Add "grabbing" cursor while dragging items:


![](https://github.com/go-gitea/gitea/assets/115237/c60845ff-7544-4215-aeaa-408e8c4ef03a)

2. Make project board only drag via their header, not via their whole
body.


![](https://github.com/go-gitea/gitea/assets/115237/62c27f3d-993a-481d-9cc3-b6226b4c5d61)

3. Fix some cursor problems in projects
4. Move shared options into `createSortable`.

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

@@ -188,8 +188,6 @@ async function initIssuePinSort() {
 
   createSortable(pinDiv, {
     group: 'shared',
-    animation: 150,
-    ghostClass: 'card-ghost',
     onEnd: pinMoveEnd,
   });
 }