NXCM-4947 - add support for JMXConfiguration to Nexus bundles

if configured, set the appropriate system properties via JSWConfig to enable an RMI registry/JMX server agent to be launched at Nexus bundle start using standard JDK 6+ system properties.

This allows monitoring a Nexus bundle remotely via JMX using RMI during test execution.

Depends on sonatype/sisu-bundle-launcher/pull/6