Use FOLIO Holding Type = Equipment instead of MARC 914

[saseestone]

Came through SearchWorks Feedback (SW-4334), from Kevin Kishimoto and was reviewed by Gryphon Core. We should stop using the MARC 914 to drive the Equipment facet. Instead, we should use the FOLIO Holdings Type = Equipment.

Folio Inventory list for Equipment at Music: https://folio.stanford.edu/inventory?filters=holdingsType.2ee101d1-d692-4004-9166-8696352e6dcc%2CholdingsPermanentLocation.b73458dd-43c3-46c2-9910-7cd76e6c697f&segment=holdings&sort=title

SearchWorks example search: https://searchworks.stanford.edu/?f%5Bbuilding_facet%5D%5B%5D=Music&f%5Bformat_main_ssim%5D%5B%5D=Equipment&search_field=search