Introduce an owl:class to capture all BHoM interfaces

Mapping both BHoM's classes and interfaces to owl:classes has created a flattening in data structure, which can be complicated to map back to the original data model.
#### Description:

To distinguish between classes and interfaces in the graph, we can create a new owl:class named BHoM_Interface; where each interface is a subclass of this new class.

this is a suggestion from: Raul Garcia-Castro - Ontology Engineering Group https://www.linkedin.com/in/raulgarciacastro/