[ruby] Download builtin package dependencies

[AndreiDreyer]

This PR handles:

• Scrape rubydoc to generate a NamespaceTypeMap for builtin ruby packages
• Generate .zip folder with MessagePack files for each of the gems to be re-used
• Write to JSON for sanity checking (to be removed)

TODO for next branch:

• Return NamespaceTypeMap from BuiltinPackageDownloader if run
• Implement reading from a ZipStream if the BuiltinPackageDownloader is not run and a .zip folder is present to build the NamespaceTypeMap

[max-leuthaeuser]

I am against putting .zip files (or any binary in general) directly into this repo.
Even with Git LFS we had trouble in the past (running into the GitHub traffic limitation, any further downloads / actions disabled).

[DavidBakerEffendi]

@max-leuthaeuser Another solution I've thought of is to treat this like the AstGen binaries, where some repo generates these and during release-time they're compressed and packaged in a minimal way. Would that be an acceptable next step? Right now I believe these are ~100mb uncompressed

[max-leuthaeuser]

Would that be an acceptable next step?

Guess thats much better, yes.

[DavidBakerEffendi]

Plan going ahead: We will not merge this PR as-is. We are going to create a separate repo that generates these type stubs, and will make releases for the language frontends that support this design (i.e., Ruby, C#)

• Releases will be MessagePack files zipped together by language, with accompanying SHA512 checksums
• Similar to AST GEN, there will be a download phase that will fetch the type stubs based on the frontend, validate the checksum, and unpack the archive to the resources folder

[DavidBakerEffendi]

This will be replaced by #4501

[DavidBakerEffendi]

Superseded by #4501