Correct group membership requests

There is a bug when clicking on a cross to remove a group from selected list in Profile page.

Check arrays used to store selected list and selection functions used in this select component.

added Frontend Priority: high labels

assigned to @remi.bisson

mentioned in merge request !39 (merged)

mentioned in merge request !41 (merged)

closed with merge request !41 (merged)

mentioned in commit 230d294e