add skos:altLabel property for mapping of instances via their name and add ogc csw harvesting pipeline (prototypical)

use skos:altLabel (not altName, sorry for the confusion) generally for alternative titles for example for organizations or repositories.

See also https://git.rwth-aachen.de/nfdi4earth/softwaretoolsarchitecture/knowledge-hub-backend-setup/-/commit/e38d96e645bbed2e49024781f87860ff43f19776

@ralf.klammer please review whether this aligns with you current work (could be used for r3d:additionalName and r3d:institutionAdditionalName). If there are no problems just merge