Add mapping between means, introspection token and NEN7512

[stevenvegt]

Each means has its own set of claims which should be accessible through the use of the introspection endpoint. So, there is a mapping from means-claim to access token field. When a care organization has to comply to the NEN7512, it should be clear how these fields compare to the NEN norm.

The challenge with this information is that each implementation can use different fields in the introspection endpoint and the NEN norm is a Dutch norm. But, we don't want to let the user search all over the place. Were do we put this?