Import polyDB metadata

[eloiferrer]

New feature description in words: Import polyDB metadata (polydb.org) into the knowledge graph.

TODOS:

• Import metadata through the Rest API (https://polymake.org/polytopes/paffenholz/polyDB-rest.html)
• Clean metadata (disambiguate authors through ORCID, retrieve DOIs for publications)
• Define new properties and items (polyDB collection, contributed by)
• Import supporting entities from Wikidata
• Create entities in the KG
• Import locally the entire polyDB dataset
• Publish the metadata in production
• Write exemplary SPARQL queries

Checklist for this issue: (Some checks for making sure this feature request is completely formulated)

• [ ] Participants in discussion have been invited as assignees
• [ ] All fields of the issue have been filled
• [ ] Example fields have been removed
• [ ] The main MaRDI project has been assigned to this issue

[eloiferrer]

Initial importer structure merged in https://github.com/MaRDI4NFDI/docker-importer/pull/70

[eloiferrer]

Metadata imported, still need to add a poly DB identifier pointing to the source.

[eloiferrer]

PolyDB metadata available from: https://portal.mardi4nfdi.de/wiki/PolyDB