2.0.0-M1

Migrate effect type to cats-effect IO. At the core, we still use akka-http for routes and clients so we need the typical akka implicits. Stream sources are also still using akka-stream. But at the interface to the backend services implemented by the calling application code, IO (or ZIO) can be used to model effect types.

It's usable as is but it is only the first milestone on the path away from Akka.