Build self container binary for tools.

[dark1587]

Request

I'd like to propose adding in support for Bazel to build python executables.

Reasoning

Several environments I've worked in the past wouldn't allow me to install 3rd-party libraries or use a venv environment. Being able to build a a pex which has said dependencies already pre-compiled solves this problem.

If I need to distribute Aerleon across multiple platforms, a Bazel bundle makes it simple to build macOS intel/arm, *nix all with a single command.