TEIIDDES-1723: Fixes rename action appearing for eObjects

* ModelExplorerResourceNavigator
 * The rename action is capable of handling both eObjects and resources
   hence little point in bringing in an alternative action from the
   ModelerActionService.
 * However, the refactor sub-menu is necessary for refactoring resources
   (since they can be moved as well) so when a resource is selected, the
   refactor sub-menu is displayed and only the rename action displayed for
   seleted eObjects.

* ModelerActionService
 * Removes the getRefactorMenu method since its functionality has been
   taken into the ModelExplorerResourceNavigator.