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

import datetime and change to utcnow() to be OPC UA conform

remove unused vars and comments
replace prints with logs

Make file write more elegant

indent formated strings in a Pep conform way
Replace os with pathlib expressions
Replace single quote with double quote
Replace multiple single lines with one string block