Support for InvenioRDM repositories

[dietervu]

At least 2 CLARIN centres recently strted using InvenioRDM:

• HZSK, example record: https://www.fdr.uni-hamburg.de/record/1697 | DOI: https://doi.org/10.25592/uhhfdm.1697
• EKUT, example record: https://fdat.uni-tuebingen.de/records/8zk89-12596 | DOI: https://doi.org/10.57754/FDAT.8zk89-12596

A third one (IDS) is on the way.

AFAIK the API for InvenioRDM is very similar to the one Invenio but would be good to double check and to make sure we have the repos above configured correctly.