Document process for Bazel usage of AutoPyBind11
Begin considering the process of running autopybind11 from Bazel:
- Capturing compiler flags: https://github.com/RobotLocomotion/drake/blob/ec5de34e0b75ff8e9ed80d0207020c11e26ec7ae/tools/skylark/pybind.bzl#L305-L421
- Circumventing input
- create yaml from Bazel or ignore it