Establish Key Commitment Registry

[dvorak42]

To avoid requiring each client using the API to develop their own key commitment registry, we're exploring having a publicly accessible key commitment registry that issuers can add themselves to and that would enforce the technical checks to verify the validity of the issuer's key commitments and key commitment updates.

One approach for this would be to have a Github repository that runs a variety of checks on update via pre-commit hooks and Github Actions to generate the appropriate key commitment files that various clients could consume for their API usage.