Design for IPA-to-IPA migration
    
    There are some references and thoughts on expanding the
    current migrate-ds plugin as well.
    
    Related: https://pagure.io/freeipa/issue/3656
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>