OO-984,OO-990: add external id and external reference to the tables of "My courses" and "Authoring environment"

OO-1230: reorder deletion of the groups of a portfolio map, add the beginning of a unit test which checks the deletion of a user

OO-1246: fetch the lifecycle and other security groups in the specialized query for institution managers

OO-1231: save null and empty values from the editor, remove unused method, check all fields in unit test...

OO-1225: remove save button for single choice in restricted mode, hardened event loop in the controller, fix the same kind of issue in essay