[Meta, Plan] Version 2.0

✨ Introduce "schematic" normalizers Active introduces core generation of content entity schema in JSON Schema format. This means the bulk of the heavy lifting in this module is unnecessary. However, we must still map the JSON Schema to entities exposed over JSON:API and provide routes, hypermedia links, etc.

This is a meta issue for migrating the module to do just this, while shedding much of the now-unnecessary schema generation logic.

In addition, I'd like to consider making this module a library for creating top-level JSON:API document schemas, and share that logic with openapi_jsonapi module. That would mean we have a single place to maintain that shared code. The schema-specific routes could be enabled through a submodule.