Extend the semantics of linking of services with datasets

Services may have several roles w.r.t. the related datasets. Those could be better described by metadata.

Services https://github.com/rd-alliance/metadata-catalog-dev/blob/master/README.md )

Grouping of services for delivery (e.g. services depending on the data or utilizing the data) for generation (i.e. part of provenance info) etc

Examples may be appreciated for considering this improvement.