Move beman-submodule and beman-tidy out of beman/infra and package them with PyPI

[ednolan]

This allows us to avoid having many extraneous files in each repo. The only thing we need in beman/infra as a beman-submodule are the CMake toolchain files.

[ednolan]

Blocked on https://github.com/bemanproject/infra/issues/181

[rishyak]

I think we're good to move it out of the infra repo. In fact, setting up on PyPI would be easier too, since I won't have to go and change links and other metadata.

[JeffGarland]

@ednolan and @rishyak did this get completed now?