Enable cost-optimized planning with STOMP

[henningkayser]

This is about enabling STOMP planning support for MoveIt 2.
The underlying implementation has been moved to https://github.com/ros-industrial/stomp, so a direct port of the old plugins is not possible anymore. I'm working on a new adaption that involves:

• Motion Planning Plugin
• Noise Generation
• Collision Cost
• Joint Goals
• Cartesian Goals
• Path Constraints
• Candidate Path Visualization

My main interest is to investigate how optimizing planners can be better supported in general. That means, I'd like to redesign or add a motion planning interface that allows passing custom costs and constraints without using the limiting MotionPlanRequest.

The current development repo is https://github.com/henningkayser/stomp_moveit. I'll move it over to ros-planning once I'm happy with it as an initial version. I'm also not planning to work on a smoothing adapter for now.

[henningkayser]

Closing this, planning and dev will be continued in https://github.com/ros-planning/stomp_moveit