IIIF Authorization Flow 2.0 Support

[joncameron]

Description

For content that requires authorization, Avalon and Ramp should implement the current Auth Flow 2.0 spec. Avalon currently has a simple implementation of IIIF Auth 1.0.

Examples

Example Stanford manifest with auth service:

• https://purl.stanford.edu/ks701xw3226/iiif3/manifest
• Some code is in here: https://github.com/sul-dlss/purl/blob/main/app/models/iiif3_presentation_manifest.rb