Proposed extensions: Hydra in OWL

[tpluscode]

I would like to propose an OWL vocabulary to augment Hydra Core.

First, it could provide OWL constructs describing the model (as an alternative to SHACL (#2))

Second, it could define additional terms to allow basic OWL-based inferencing. Off the top of my head, we could have inverse properties

howl:operationSupportedByClass 
  owl:inverseOf hydra:supportedOperation ;
  rdfs:domain hydra:Operation ;
  rdfs:range hydra:Class .

howl:operatonSupportedBy
  owl:inverseOf hydra:operation ;
  rdfs:domain hydra:Operation ;
  rdfs:range hydra:Resource .

howl:propertySupportedByClass
  owl:inverseOf hydra:supportedProperty ;
  rdfs:domain hydra:Operation ;
  rdfs:range hydra:Class .

This way instances, and terms from external vocabularies could be extended with Hydra affordances without "polluting" their immediate graphs