Write tutorial for MoveIt 2 + Ignition Gazebo Integration

[vatanaksoytezer]

[sea-bass]

To add to this issue, we were informed in https://github.com/ros-planning/moveit2/issues/2630 that Jazzy will no longer support Gazebo classic... so we should probably have something by then.

https://github.com/henningkayser/moveit2_tutorials/blob/panda_gz/doc/examples/motion_planning_python_api/motion_planning_python_api_tutorial.rst#running-the-tutorial-in-a-gazebo-simulation is a good starting point.