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.
The Programs authoring app is a Backbone SPA maintained in a separate repository. The app handles its own routing and provides a UI which can be used to create and publish new Programs (e.g, XSeries). ECOM-2598.
