Providing a hermetic python toolchain

For serious use-cases we would benefit from a system-independent python toolchain that can source an interpreter. At the basic level this involves downloading a copy of CPython for the current platform that can run code. An issue with this is that basic cpython depends on dynamic libraries such as libssl and libsqlite, so we need to either provide a mechanism for building those consistently (c / cpp compiler) or use an interpreter with static linking such as https://python-build-standalone.readthedocs.io

## Potential learnings from bazel

- dependencies are managed in a repo rule, meaning they are not using the same toolchain that bazel uses, but use the local toolchain
- cross compilation is tough (broken)