DPROD — Consider aligning input/output ports with PROV

See https://github.com/EKGF/dprod/issues/76
I would have expected either:
inputDataset and outputDataset to be modelled using prov semantics (either just as prov:wasDerivedFrom/prov/used or as a subProperty of it).
or, if the semantics is distinct from prov, that the nuance is clarified at the very least in the documentation, but ideally also through machine readable relationships (something like owl:differentFrom).