Consider moving Bicep exensibility type generation out of the repo

[rynowak]

Summary

We have a checked in copy of the Bicep extensibility types in the repository, including the tools needed to generate them.

Nothing in the Radius repo consumes these types and they are only used by our automation. This is in contrast with the other generated artifacts like the swagger files that do get used in the repo to generate go code.

It would be better if we can remove these to simplify the repo for contributors. Most contributors will not be updating types or interacting with the generators.

Details

We have two primary "generation" flows that take place:

Go code:

CADL -> OpenAPI -> Go APIs and Client

Bicep types:

CADL -> OpenAPI -> Bicep Types -> PR to project-radius/bicep

The Go code workflow starts and ends in this repo. Ultimately we want the Go code workflow to end in this repo because that's where the Go code needs to be.

The Bicep types workflow starts in this repo and results in a PR to another repo. The tools for this are a checked in copy of code that lives elsewhere. We have a checked in copy of the bicep types, which are not consumed by anything in this repo.

Suggested improvements

We can definitely refactor to avoid checking in the Bicep types. This removes a thing that's going to make contributors go huh? when they see it.

We should find a better solution to sharing the bicep type generator code. Having a checked in copy in this repo is not great.

We should consider whether the CADL types and swagger files should live elsewhere (outside of Radius).

AB#8076

AB#9509