Enhance migration service to check parent/sub-process relations

In some cases during our migration we migrated either the parent process instance or the child process instance while the child process instance was being completed. Having the parent process instance in a container, while the child process instance is in another container has caused the child not being able to communicate to its parent about the child completion. Please provide a migration service that migrates the parent process instance along with its child processes in a way that we can't interact with a process until all its tree is migrated.

Migration service that automatically migrates child process instances.