These changes have 3 different scope:
1) This change will allow to extend the dsreplication userdata objects.
2) The set of modification will also allow to extend the server
    descriptor used by the internal admin
3) With the current implementation, if the server is configured
    in manual mode, backend cannot be disabled (admin framework
    will check aggregation constraint for this associated
    LocalBackendWorkflowElement). This will block the import
    for instance.
    The modification relaxes this constraint.