DataManagementSetup implementation should be independent

[mpostol]

From the description, I can guess that the project provides two independent implementations of the DataRepository, According to the ReferenceApplication example and the architecture presented in https://commsvr.gitbook.io/ooi/reactive-communication/semanticdata#reactive-networking-application-architecture both need independent implementation of the DataManagementSetup. It promotes separation of concerns and reusability. Unfortunately, I can find only one implementation of this class, namely NetworkEventsManager.

It must be recognized as a data error, so some comments are required.

[Drutol]

That's true, I acknowledge that it should be separate, yet I have run into a bit of trouble which I have described here: mpostol/OPC-UA-OOI#468

[mpostol]

Not sure if adding abstract may be recognized as a real relief. Anyway, it is done. I have also improved documentation in this respect.