cleanup 2024-03: unreplaced retirements
    
    Also removes the mongodb group entirely, because it isn't really
    serving a purpose any more. It was originally meant to contain
    the mongodb server itself, but that got removed years ago for
    non-free licensing. There's no real use to a group which just
    has a random client library in it.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>