feat(calendar): add copy to clipboard button in "links to calendar" panel

UI/WebServerResources/js/Scheduler/sgCalendarListItem.directive.js

@@ -293,10 +293,16 @@
             var vm = this;
             vm.calendar = calendar;
             vm.close = close;
+            vm.clipboard = clipboard
 
             function close() {
               $mdDialog.hide();
             }
+
+            function clipboard(elem_id) {
+              let linkUrl = document.getElementById(elem_id);
+              navigator.clipboard.writeText(linkUrl.value);
+            }
           }
         };