TODO for RT-Extension-ReferenceIDoitObjects

* [Bug] Show link to modify referenced i-doit objects in the page navigation.
* [Feature] If initial loading takes too much time => show loading animation.
* [Feature] Add user/group right to modify referenced i-doit objects.
* [Feature] Make field for email addresses configurable (currently only
  'Requestors').
* [Feature] Add check box in table header to select all objects in list.
* [Feature] Add button/link in table header to remove all selected objects from
  list.
* [Feature] Add new tab to search for i-doit objects.
* [Feature] DataTables: Filter only by some columns.
* [Feature] Create more translations.
