Make roles for sms configurable

Together with Martin & Marie we discussed that we want to make our roles configurable - so that we don't hardcode the 'Admin' & 'Member' role when extracting the group information from the HIFIS virtual organizations.

This way we can allow role names like 'gfz.sms.member' or 'gfz.sms.admin', etc. With Marie we also discussed that we still want to have some kind of 'default' role, so that the virtual organizations group can be used for multiple tools (and not to have the member role to be sms specific).