@Override
  public Map<String, String> toMap() {
    return configurationMap;
  }
Given a String containing PEM-encode x509 certificate, an {@link RSAPublicKey} is created and
returned.
<p>
If the certificate data is does not contain the proper PEM-encoded x509 digital certificate
header and footer, they will be added.

@param certificate a PEM-encode x509 certificate
@return an {@link RSAPublicKey}
ambari-server/src/main/java/org/apache/ambari/server/security/authentication/jwt/JwtAuthenticationProperties.java