Remove ipa-replica-prepare script and man page
    
    This is part of the DL0 code removal. As ipa-replica-prepare is only needed
    and useful for domain level 0, the script can be removed.
    
    See: https://pagure.io/freeipa/issue/7689
    Signed-off-by: Thomas Woerner <twoerner@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>