Implement OpenRefine API

(the idea is that the Vocabulary Registry can be added as reconciliation service to Open Refine):
- https://openrefine.org/docs/manual/reconciling
- https://www.w3.org/community/reports/reconciliation/CG-FINAL-specs-0.1-20230321/

-moved from team-structured-data-backlog, created July 16, 2024-