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/helpers.less

@@ -30,7 +30,7 @@
 .list-divide-items li + li {
     margin-top: 13px;
     padding-top: 13px;
-    border-top: 1px solid #EEE;
+    border-top: 1px solid #cdcdcd;
 }
 
 /*===================================================
@@ -1168,19 +1168,19 @@
 
 /* Default Borders */
 .br-a {
-    border: 1px solid #EEE !important
+    border: 1px solid #cdcdcd !important
 } // "-a" = all sides
 .br-l {
-    border-left: 1px solid #EEE !important
+    border-left: 1px solid #cdcdcd !important
 }
 .br-r {
-    border-right: 1px solid #EEE !important
+    border-right: 1px solid #cdcdcd !important
 }
 .br-t {
-    border-top: 1px solid #EEE !important
+    border-top: 1px solid #cdcdcd !important
 }
 .br-b {
-    border-bottom: 1px solid #EEE !important
+    border-bottom: 1px solid #cdcdcd !important
 }
 
 /* Border Style */