This release of the model catalog assigns SVOs identifiers to local URIs (of type https://w3id.org/okn/o/sd#StandardVariable).
Thanks to this change, the local API will have less trouble distinguishing ids. In addition, when a new SVO is created, we don't need to have a mechanism dependent on SVO.
All ids that correspond to an SVO are preserved with an owl:sameAs. Some of the descriptions from existing SVOs are also imported for consistency