Although we are phasing out our support of OIDC, this particular feature will allow us to eliminate many of the settings we
share across services. Instead of reading various endpoints and secret keys from settings or hardcoded values, services
with the proper authentication backend can simply read (and cache) the information from this endpoint.

ECOM-3629

This information mirrors the fields returned in our ID token for OpenID
Connect (OIDC). Including this information will allow us to eventually
migrate toward replacing OIDC with OAuth 2.0 + JWT.

ECOM-3628

We should not be using custom signing keys for each service at this time. We may want to return to this strategy in the future; but, this is not the direction any of our other services are going in.

ECOM-6541

2. Add site configuration overrides to theming/helpers.py
3. Move microsite.get_value from theming/helpers to site_configuration/helpers
4. Move microsite_configuration.microsite.get_value usages to site_configuration.helpers.values

These changes unify four different approaches to JWT creation, moving the core of the AccessTokenView to a general-purpose JwtBuilder class. This utility class defaults to using the system's JWT configuration, but it will allow overriding of the signing key and audience claim to support those clients which still require this. Part of ECOM-4566.

ECOM-4441

ECOM-3528

Extends the Programs ConfigurationModel, cleans up Programs-related utilities and corresponding tests, and corrects caching. Uses the Programs API to list programs within Studio. ECOM-2769.