Identify OAI records to be harvested by D4Science

small set of OAI records for CMIP6 data next:
these records should address cmip6 collections for which we have a (subset) on openstack and for which we can provide an intake catalog
1. step: include http ref to intake catalog as part of identifier info in OAI record
1. step: t.b.d. use separate way to link OAI-record id with intake ref for D4Science catalog ..