IMPROVEMENT: replace References with IsSupplementedBy for auxilliary semantics

[agy-why]

The #auxilliary semantics from IVOA datalink (https://www.ivoa.net/rdf/datalink/core/2022-01-27/datalink.html) refers to the References relationType from datacite 4.4 (https://schema.datacite.org/meta/kernel-4.4/doc/DataCite-MetadataKernel_v4.4.pdf).

From the definition of References: Indicates that B is a source of information for A it does fit. However from the usage it seems it fits better for citation of articles, not for data publication.

However another relationType: IsSupplementedBy defined as: Indicate that B is a supplement to A (recommanded for discovery) seems to better fit, since we use the datalink semantic #auxilliary for discovery purposes.

So I suggest to change our implementation and replace the relationType of the OAI entries referred as #auxilliary to IsSupplementedBy instead of References.