WF-CORE 75: Remove need for native-interface on the Host Controller

Jira: https://issues.jboss.org/browse/WFCORE-75
This is a 3 commits PR : 
 * the first part is about enabling HC- DC communication using any of the 3 supported remote procotols
 * the second is about using the management interfaces defined in HC to be passed automatically to the slaves using the ProcessController.
 * the third is about testing
Hum I don't think a new variant is needed since without the XML attribute the default value will be used.