[NRRPLT-4885] Cleanup ROS nodes created by distributed launch.

The distributed launch now creates a ROS node in the CLE to ensure
logs are properly redirected to stdout. This node and any future nodes
should be cleaned up as we do in the CLELauncher, but this needs to be
done after shutdown of all launched components.

Change-Id: I00733872978d13cf4c3f319c7e594feae866d930