Support process migration from one runtime manager to another.

Support process migration from one runtime manager to another.

The current jbpm api call could migrate a process running in one runtime manager(context). In a situation when trying to migrate a process running in runtime manager A to a different B, it does't work. This RFE is seeking the support to migrate the process running in one runtime manager to another.
The use case that drives this RFE is that users deploy a kjar with one releaseid and load it to a kiesession. They deploy a newer version of kjar later and load it to a new kieSession with the new release id. They would like to migrate the processes running in the old kiesession to the ones running in the new kiesession.