Retrieve records from the OCLC Metadata API based on OCLC number

[mzelesky]

As part of the work to update series handling to current standards, I need to be able to retrieve MARC records from OCLC via the Metadata API based on OCLC number.

See https://developer.api.oclc.org/wc-metadata-v2#/Manage%20Bibliographic%20Records/bib-read for more details on the Metadata API.

This API uses OAuth2 authentication.

Acceptance criteria:

• A class is created to authenticate via OAuth2 authentication based on an OCLC WSKey combined with a client secret
• A class is created to retrieve a MARC record from the Metadata API
• A class is created to retrieve MARC records from OCLC for an arbitrary number of OCLC numbers.
  • The class handles reauthorizing OAuth based on time elapsed