JBTM-432 - Authentication support on AppServerJDBCXARecovery plugin

This allows the jmx username/password to be specified in the jbossts-properties.xml and allows the AppServerJDBCXARecovery plugin to
function when the invokers are secured.

Customers do not like having username / passwords in clear text in the jbossts-properties.xml and do not understand why the username / password has to be set in the first place. Providing encryption support for the user/pass in the jbossts-properties.xml or better yet integrating it better so that the user/pass is not required when using secure invokers would be nice.