[reva.mesocentre.universite-paris-saclay.fr] Ajouter la gestion des groupes d utilisateur

ldaps.universite-paris-saclay.fr currently add all user on same group that disable the ability to share some cephfs directory between users. We have to work w/ DSI Universite-Paris-Saclay to create some group that will be expose to mesocentre.universite-paris-saclay.fr and modify group right access to 0770