Switch to DataCite REST API, 4.3 schema, and add prefix options for tech report

This major release switches from using the DataCite MDS API to the DataCite REST API. It updates the metadata schema for DataCite 4.3 and adds in a ROR Affiliation Identifier for CaltechTHESIS records.

Operationally both the CaltechAUTHORS and CaltechTHESIS scripts now update DOI metadata with DataCite, instead of providing the user the option to overwrite DOIs in the Eprints record.

The new prefix option in caltech_authors_techreports allows users to mint DOIs for groups that use a non-Caltech Library prefix. All code has also been formatted with the Black code formatter.

If you're upgrading, please uninstall the datacite library with pip ininstall datacite and reinstall the new version with pip install -r requirements.txt from within the epxml_to_datacite folder.