adds a groups handler to fetch groups/remote from the remote auth provider, similar to what done with user info
TODO: update the roles table when groups fetched, setting the unique id of the role and the is_managed field. The roles in the DB managed by the external auth should be in sync with the ones fetched for the logged in user.
groupshandler to fetch groups/remote from the remote auth provider, similar to what done with user inforolestable when groups fetched, setting the uniqueidof the role and theis_managedfield. The roles in the DB managed by the external auth should be in sync with the ones fetched for the logged in user.