Added additional property shapes on commons/minds schema

[annakristinkaufmann]

It was agreed to add the following two property shapes to the commons/minds schema (which is imported by the morphology/neuronmorphology schema):

• nsg:atlasRelease
• nsg:isRegisteredIn

These two property shapes will eventually be captured in a brain-independent spatial location shape.

FYI @jonathanlurie @MFSY