Add control process for VPN access

[RuCaVi]

Add a control process to verify if an AD account has access to VPN connexion. For that, check that it is in the correponding security groups (ask Didier Delessert to know what groups are concerned). In the application interface, add an information in the user detail screen to let know if a user has access to VPN or not.

An AD account has access to the VPN if it's member of gs-vpn-col or gs-vpn-corona. Attention, accounts can also be member of a group which is itself member of a VPN group.

Example :

• myADaccount is member of gs-vau-ede
• gs-vau-ede is member of gs-orif-ede
• gs-orif-ede is member of gs-vpn-col
• myADaccount has access to the VPN

[DidierViret]

Add a link to the function "Liste des accès VPN", which displays a list of all AD accounts having the rights to access VPN. Add a table on the right in the user detail interface, with one row and two columns, "VPN" in left column "YES" in green or "NO" in red in the right column.