Use hermetic python toolchain provided by rules_python

[ylecornec]

rules_python now provides ways to download and setup hermetic toolchains for bzlmod and workspace mode.

For non nix systems, this could possibly be used instead of our own implementation which uses python3 from the environment.

Note: The last version of rules_python also registers a default toolchain but is does not work when bazel is run as root (see bazelbuild/rules_python#1169). This behavior can be changed usingignore_root_user_error = True as an argument, but this badly effects caching (see bazelbuild/rules_python#713).

rules_haskell/haskell/ghc_bindist.bzl

Line 558 in cdde0d0

def _configure_python3_toolchain(name, register = True):