fix JMX

set up all JMX-based routines to share common code, which chooses JMXMP or JMX-RMI agent, or no JMX agent (JMX default), or no JMX; some with security; based on configuration -- see JmxSupport.JMX_AGENT_MODE and others

tested in a variety of configurations, confirm default (JMXMP) works to deploy JMX-based entities to clouds like HP's where the hostname and internal IP are different to the hostname and public IP we want to use