Demo with MTC, Pilz planner and a simple weld seam

[christianlandgraf]

This PR aims at including a simple demo case, which loads a single weld task description to the corresponding workpiece in the

For testing the demo as described in the README, the following things need to be done

• Fix the ros2_control API change in ros2_control_demo and the UR driver
• Copy the pilz_industrial_motion_planner from the PR in your local clone.

The PR does not include yet:

• "processit_tasks" is neither integrated nor fully migrated to ROS yet
• The workpiece position is hardcoded and not automatically retrieved from the planning scene yet

[christianlandgraf]

Wow, this is so much new code. I'm not sure if I can really review all of this in depth, but I will test this and provide fixup where adequate. There are definitely some things that could be improved, but I don't think we should go over board with optimizations for this demo (yet). Could you resolve the conflicts with master?

Thanks for having a look at it! I think you can skip most of the processit_*/... stuff since it is not focus of the demo and needs a lot of improvement anyway :D I will resolve the conflict and try to give a better description in the PR today

[christianlandgraf]

I addressed the first reviews and fixed a minor bug(?) with the MTC namespace.

As far as I can see now the main thing which keeps the CI from build are the ros2_control API changes and the pilz_industrial_motion_planner, which I manually copied from the porting PR