Add support for dual authentication

AFAIK, Artemis currently supports only one type of authentication that should be configured in login.config. So one can use either PropertiesLoginModule or CertificateLoginModule but not both.

In our environment, we use both plain and X.509 authentication. ActiveMQ 5.x does support dual authentication via the jaasDualAuthenticationPlugin. For more information, see https://access.redhat.com/documentation/en-US/Fuse_ESB_Enterprise/7.1/html/ActiveMQ_Security_Guide/files/Auth-JAAS-DualAuthentPlugin.html.