V2 conversion

[NullVoxPopuli]

I decided to see what is blocking while doing the whole conversion in one go

Pending

• convert ember-source to v2 (too much weird stuff is happening with the virtual packages rn)
• update ci
• finish conversion
• resolve build tooling issues
• upstream patches
• convert to pnpm

Things preserved:

• the way public-types are built
• addon is compiled via babel (but via rollup)
• test app can import private APIs

Breaking changes:

• no longer supports setResolver as setApplication already sets up an event-dispatcher, and for complexity reasons, support for custom event dispatcher has been removed in createCustomResolver

Non-Breaking changes:

• consuming node version doesn't matter (this is a browser only bundle)
• build-registry no longer uses private AMD apis, and instead uses embroider/macros
• tests no longer use private AMD apis
• ember-data is an optional peer dependency (for calling setupContainer)

once all core ember addons are v2, we can much more easily do vite/vitest tests in non-monorepo repos (lots of cool things are unlocked once we drop broccoli / v1 addons entirely -- single-repos become an option again!).