Drop python2

[Atemu]

python2 is used for compat with older versions of Android it seems. We should either:

1. Drop it entirely
2. Make python2 optionally available for old android versions; requiring the user to opt into insecure which I think is appropriate
3. Use python2 from 22.11 into eternity

I'm gravitating towards 2, perhaps resorting to 1. if that turns out to be too hard.

What we should do in any case is getting rid of python2 for deps. It remains to be seen how possible that is or whether we need to resort to 1. here aswell.

Related: #218

[Janik-Haag]

just fyi, trying to build grapheneos with a current version of nixpkgs unstable doesn't work because python dependencies break numpy-1.26.2 not supported for interpreter python2.7