Deactivating registrations

This issue should be considered along #278

In most cases registrations shouldn't be deleted but marked as deactivated.

Access Authorization

We need a clear way to deactivate authorizations. Since they are immutable, it most likely should be an Access Authorization which states that access was rejected. (related to #278)

Agent Registration

While Application Registration always should have an Access Grant, it is not required for Social Agent Registration.
I think we should answer if we only need an Access Grant that reflect mentioned above Access Authorization which gives not access. Possibly we want to make the whole registration as inactive, this could be used in #138 where user needs to select agents they want to grant access to. The deactivated ones would not appear in the list.

Data Registration

This one probably needs some clear use cases. I'm not sure what deactivating data registration would mean. Also what would happen if access is requested for shape tree registered in deactivated data registration.