fix(calendar(js)): allow event invitations to be moved

Fixes #4926

UI/Templates/SchedulerUI/UIxAppointmentViewTemplate.wox

@@ -49,7 +49,7 @@
                 </md-menu-content>
               </md-menu>
             </md-menu-item>
-            <md-menu-item ng-hide="::editor.component.isReadOnly">
+            <md-menu-item ng-show="editor.component.isMovable()">
               <md-menu>
                 <md-button label:aria-label="Move To" ng-click="$mdMenu.open($event)">
                   <var:string label:value="Move To"/>

UI/WebServerResources/js/Scheduler/Component.service.js

@@ -694,13 +694,25 @@
   /**
    * @function isInvitationOccurrence
    * @memberof Component.prototype
-   * @desc Check if the component an invitation and an occurrence of a recurrent component
+   * @desc Check if the component is an invitation and an occurrence of a recurrent component
    * @returns true or false
    */
   Component.prototype.isInvitationOccurrence = function() {
     return (this.occurrenceId && this.userHasRSVP);
   };
 
+  /**
+   * @function isMovable
+   * @memberof Component.prototype
+   * @desc Return true if the component can be moved to a different calendar which occurs in two cases:
+   *       - the component is editable, ie is owned by the current user;
+   *       - the component is an invitation and the current user is an attendee.
+   * @returns true or false
+   */
+  Component.prototype.isMovable = function() {
+    return (!this.isReadOnly || this.userHasRSVP);
+  };
+
   /**
    * @function showPercentComplete
    * @memberof Component.prototype