https://github.com/FreeOpcUa/opcua-asyncio/issues/457

* Add method to add reverse references, if missing

* Replace NodeId numbers with ObjectIds
Fix bug - check if Node even has references, since a Node may be empty

* Fix wrong used Nodes to check

EffectiveTransitionTime will be reintroduced with the substatemachines

Use datetime.utcnow instead local now

Replace os with pathlib expressions
Make write process more visual