[make_wheel.yml] Also build wheels with ubuntu-20.04 (glibc 2.31)

[make_wheel.yml] Build wheels with LuaJit, and add MacOS/ARM64.

Build wheels and precommits with LuaJit and for MacOS/ARM64.

Affects [bazelrc, precommit, make_wheel, luajit.BUILD].

Building for ARM64 on the x86_64 GitHub action runners uses
cross-compilation. We add a new configurable setting to allow the
genrules that are executed on the host to be aware of the intended
target architecture, and we set this setting's value via a command
line flag subsumed by the "macos_arm64" config in our .bazelrc.

Since the build results are not runnable on the GitHub x86_64 runners,
we don't run the unit tests in those configurations.

[make_wheel.yml] Build wheels for macos-{11,12,13}, and Py 3.{8-11}

[make_wheel.yml] Build wheels with optimisations

[grid_world] Use Lua stack more efficiently.

This avoid previous stack overflows in situations where many states
and hit types were being created, and is all around a better use of
resources.