ipa-replica-install: password and admin-password options mutually exclusive
    
    Currently it is possible to run ipa-replica-install in one step,
    and provide --password and --admin-password simultaneously.
    This is confusing as --password is intended for one-time pwd
    when the ipa-replica-install command is delegated to a user
    who doesn't know the admin password.
    
    The fix makes --password and --admin-password options
    mutually exclusive.
    
    Fixes https://pagure.io/freeipa/issue/6353
    
    Reviewed-By: Christian Heimes <cheimes@redhat.com>