Update Instrument identification for DataCite schema 4.5

As specified in the DataCite schema update (https://schema.datacite.org/meta/kernel-4.5/), the new standard way to identify scientific instrumentsin DataCite records is via the type:

resourceTypeGeneral

"Instrument"

Example usage: https://api.datacite.org/dois/10.5442/ni000024.

Please refer to @gabriel.preuss for details.