Load certificate files as binary data
    
    In Python 3, cryptography requires certificate data to be binary. Even
    PEM encoded files are treated as binary content.
    
    certmap-match and cert-find were loading certificates as text files. A
    new BinaryFile type loads files as binary content.
    
    Fixes: https://pagure.io/freeipa/issue/7520
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>