Expand SHACL validation #44
Description
While I don't think there are any more violations of data models in the ontology (outside of #27) and some constraints are not implemented in SHACL just because they're not needed, I think it would be a good idea to implement them to allow the growth of the project. Some other rules utilizing the sh:Warning and sh:Info levels could also be used for implementing some general quality guidelines for ontologies using SKOS, like for example here: https://github.com/cmader/qSKOS/wiki/Quality-Issues.