Revert clap from arg parsing during setup

[jaisnan]

--help and --version commands were being overriden by clap, so we are going back to the simple parsing with the added logic for use-local-toolchain.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[celinval]

I think we should unblock the release by merging this, but if you want to try re-adding clap later, you can disable the parser --help and --version

[jaisnan]

I think we should unblock the release by merging this, but if you want to try re-adding clap later, you can disable the parser --help and --version

Yeah, I just wanted to go to a quick solution we know works for sure. In the meanwhile, I'll try to refactor this change to use clap with those options.