Deprecate & archive this module, or remove fontTools.cu2qu?!

[behdad]

I don't remember why cu2qu was imported into fontTools. At any rate, let's do whatever is needed to deprecate one of them. @anthrotype can you elaborate what the outstanding issues are?

cc @simoncozens

[anthrotype]

the only outstanding issue is that for this standalone cu2qu we build and publish cython-accelerated, pre-compiled native wheels for a range of supported python versions and platforms to PyPI (via the wheel builder CI at https://github.com/anthrotype/cu2qu-wheels), whereas for fonttools we keep it pure-python by default (unless one opts in and has cython and a compiler toolchain and builds fonttools from source), and for fonttols we only build and publish a pure-python wheel to PyPI.

I suppose we can do the same and make a repo (fonttools/fonttools-wheels) whose only purpose is to build and publish native wheels at each tagged fonttools release.

Then there's no longer need to have this standalone cu2qu, and ufo2ft/fontmake/etc. can switch to fontTools.cu2qu.

Another option is we forgo of the cython acceleration for cu2qu, which I remember you saying it is not that exciting after all (given all the pure-python optimizations you went through already), and simply drop and archive this standalone cu2qu and simply use the pure-python copy in fontTools.cu2qu.