Move RLC Emitter into the Typespec Repo

[joheredi]

No description provided.

[joheredi]

Moving RLC is not out of the picture in the long term, we are still considering it, just not in the scope of this semester. @bterlson has received feedback from 3p that they need its footprint to be even smaller to be useful, we think we can achieve this with a dependency-less RLC, however the priority for this semester will be to move Modular only.

We'll keep generating RLC specially as the default for Azure, but it will be through @azure-tools/typespec-ts instead of @typespec/http-client-javascript (this will be modular)