ipatests: add a test for ipa-replica-install --setup-ca --http-cert-file
    
    The options *-cert-file are used for a CA-less replica installation and
    are mutually exclusive with --setup-ca.
    Add a test for this use case.
    
    Related: https://pagure.io/freeipa/issue/8366
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>