Improve resource claiming for Cartesian command handles

[stefanscherzinger]

The current implementation of Cartesian command handles allows to run joint-based and Cartesian-based ROS-controllers in parallel (see e.g. here). While technically they do not claim the same resources and hence could run in parallel regarding the ROS-Control philosophy, some drivers go for an either-or-approach.

Let's rethink resource handling for these cases.

[fmauch]

Closing in favor of UniversalRobots/Universal_Robots_ROS_passthrough_controllers#1