Replace setup.bash with ament_environment_hooks

[clydemcqueen]

Refer to https://github.com/gazebosim/ros_gz_project_template/tree/main/ros_gz_example_gazebo/hooks

[clydemcqueen]

https://colcon.readthedocs.io/en/released/developer/environment.html#dsv-files

[clydemcqueen]

We can use colcon to build [almost] everything and manage [most of] the environment. This will simplify the build process and allow us to get rid of setup.bash.

Tasks:

• Add orca_description/hooks/setup.dsv, and modify orca_description/CMakeLists.txt to call it
• Add ardupilot_gazebo to workspace.repos
• Add ardupilot to workspace.repos; this will provide the ardupilot_sitl ROS2 package
• Modify Dockerfile
• Modify README.md