Fix user management in JSF UI when editing user groups

Take a big organization with 100k users and 10k groups and some groups containing almost all users.

Then follow this scenario

1. search for a user
2. edit the user groups to add it to a group which contains 50k memberss
3. save the changes

This query will fail because of the size of the request which brings all the group members ids.

The manipulation of the groups should not carry all the group members.