Certificate management with self-signed CA
    
    The certificate_status_widget has been modified to check for the
    environment variable ra_plugin to determine the CA used by IPA
    server. If self-signed CA is used, some operations will not be
    available (e.g. checking certificate status, revoking/restoring
    certificate), so the corresponding interface will be hidden. Other
    operations such as creating new certificate and viewing certificate
    are still available.