makepanda: Start a makepanda-compatible wrapper around CMake

[Moguri]

This script currently resides at makepanda/makepandawrapper.py but could be moved to makepanda/makepanda.py if/when the wrapper becomes good enough to drop makepanda.

Some known issues:

• Not all package options have been mapped to CMake (e.g., --use-tinydisplay)
• Not all documented flags have been implemented (e.g., --wheel)
• Not all flags were documented (e.g., --clean)

[Moguri]

It's still pretty rough, but I think this script is in a sharable state, and it should be pretty easy for anyone to extend. At the very least, if there are issues with where this is going, it would be good to get them sorted out now.

[rdb]

I like this. I'd like to get this to replace makepanda in the repo once a few more things are supported.

Besides command-line options, I'd like this to also support setting THIRDPARTY_DIRECTORY from the MAKEPANDA_THIRDPARTY environment variable.

[rdb]

It'd also be good to set WANT_PYTHON_VERSION to the version of Python that makepanda is being invoked with.

[Moguri]

Rebasing this so CI checks run

@rdb, I believe all previous review items have been addressed. Any thoughts on next steps or further required changes?