Human readable labels for Data Instances, needed when selecting instances on consent screen.

[elf-pavlik]

Something super generic like rdfs:label should work. Authorization Agent showing the consent screen doesn't know about domain-specific vocabs so it needs something generic when showing a label to a user.

Another approach might be that a shape tree specifies the predicate that should be used as a label for data instances.

[elf-pavlik]

#299 notes:

@elf-pavlik: Currently st:describesInstance is used on shape tree description, which is associated with some human language. We only need it on the shape tree level itself, similar to st:shape. The value would be a predicate which is also used as one required by the shape associated with the shape tree.
@justinwb: tracking in shapetrees/specification#77