RDF ConverterPlugin for authority values

[floriangantner]

Is your feature request related to a problem? Please describe.
Currently the RDF-Generating MetadataConverterPlugin in DSpace7 can only generate text-based values from metadatavalues.
https://github.com/4Science/DSpace/blob/bf5b19b6da561a9fc2e088dc1b376987c8115760/dspace-api/src/main/java/org/dspace/rdf/conversion/MetadataConverterPlugin.java#L159C6-L159C6

DSpace-Cris usually holds references to other entities in authority values. These relations/connections/links are useful for RDF graphs.
Because the normale Dspace does not use authority values but relation instead we see this as some DSpace-Cris problem.

Describe the solution you'd like
We would like some ConverterPlugin which considers metadatavalues with authority. If the authority is some internal reference which is publicy available, than as the RDF-object some resource with the corresponding IRI should be created.

Describe alternatives or workarounds you've considered
It could also be possible to use some xml-Crosswalk and corresponding generators to generate the rdf.
This problem mainly concerns you if you want to reuse your data as rdf in other systems or fill some triple store with relevant data.

Additional context