Revise FiggyReport class to retrieve the full Figgy report of objects to MMS IDs

[mzelesky]

See https://github.com/pulibrary/bibdata/blob/eb1aa5192521f3ee32d03af965027238f2e31c23/app/models/mms_records_report.rb#L16

Acceptance criteria

• Class uses a token to authenticate and retrieve the report
• Class outputs an array of FiggyDigitalObject objects

[mzelesky]

Because the class outputs FiggyDigitalObject objects, that class needs to be updated first.