Mixed python/cpp Ament package

[wjwwood]

The closest thing I know of is how catkin from ROS 1 combines CMake and Python:

• https://github.com/ros/catkin/blob/kinetic-devel/cmake/interrogate_setup_dot_py.py
• https://github.com/ros/catkin/blob/5a7f61d594a56ca4b3ae1705e64140e9f29e0bd7/cmake/catkin_python_setup.cmake#L63