Update styles and add task priority feature

- Changed border color from #eee to #cdcdcd in various CSS files including dropzone, mapplic, summernote, grid, and select2 to enhance UI consistency.
- Added a new task priority selection feature in the task popup, allowing users to change the priority of tasks dynamically via AJAX.
- Implemented AJAX functionality to handle task priority changes and update the task list accordingly.

libraries/framework/skin/base/components/navbar.less

@@ -325,7 +325,7 @@
     padding: 10px;
 
     /* Media Item - Top Border */
-    + li.media { border-top: 1px solid #EEE; }
+    + li.media { border-top: 1px solid #cdcdcd; }
 
     /* Media Item - Image */
     > a {