ProcessManagerInstance uses the ProcessManagerActor as subscription address.
ProcessManagerActor spec.
Add composite identifier.
Use CompositeIdentifier for SubscriptionId.
Add unapply for composite identifier.
Organize imports.
Forward aggregate events from manager to instance.
Extract sharding logic into ShardedActor and rename AggregateManager to AggregateActor.
Pass sharder reference to sharded actor.
Write process manager actors as sharded actor and merge it with process manager instance.
Also merge tests of PMA and PMI.