Add Physical Format to Descriptive Metadata

[joncameron]

Description

Physical format can be defined out of band in Avalon and show up in facets and in the interface, but there is no current capability for users to add or edit this field. Avalon should be able to accommodate physical carrier information for items, particularly for media which is not born-digital.

Could use the controlled vocabularies in PBCore: https://pbcore.org/elements/instantiationphysical