2.0: Async + Revised watcher

[orta]

2.0.0

• Redwood uses prettier 3, and prettier 3 removes the sync API. This means we now have to operate entirely async. This is a breaking change from the sdl-codegen API, as you need to await the exposed public fns.
• There is a verbose option which provides info on the timings of the codegen.
• Big watch mode improvements