HybridPlanningManager should not inherit from Node

[AndyZe]

See moveit_ros/hybrid_planning/.../hybrid_planning_manager.h

Discussion here. https://github.com/ros-planning/moveit2/pull/980#discussion_r787230230

This likely causes some initialization issues. There is a sleep in the constructor.

[henrygerardmoore]

I'm going to take a look at this