Move controller_manager/ traj_execution_manager documentation to tutorials

[AndyZe]

There is some documentation scattered around the codebase. For example,

https://github.com/ros-planning/moveit2/blob/main/moveit_plugins/moveit_ros_control_interface/README.md

https://github.com/ros-planning/moveit2/tree/main/moveit_ros/planning/trajectory_execution_manager/dox

It would be nice to consolidate this to the tutorials. Probably here: https://moveit.picknik.ai/humble/doc/examples/controller_configuration/controller_configuration_tutorial.html