ship mpy-cross similar to micropython-uncrustify

[jepler]

Recently micropython dealt with the difficulty of getting the right uncrustify version by creating a micropython-uncrustify package. This looks like it'll install on windows, linux & mac.

we could do mpy-cross the "same way", probably having an mpy-cross- package so that different mpy-cross binaries are co-installable.

then, use this in circuitpython-build-tools, get rid of all the hard coding of download paths in various tools, etc.

[dhalbert]

GMTA. This was just added to pypi: https://pypi.org/project/mpy-cross-multi/

see https://github.com/orgs/micropython/discussions/15176

[jepler]

I wonder if we could ask mpy-cross-multi to support circuitpython 😉

[jepler]

mpy-cross-multi seems to be built on various mpy-cross pypi packages like https://pypi.org/project/mpy-cross-v5/ which are possibly generated from branches of https://github.com/pybricks/python-mpy-cross