Robotics Systems Types

rst-converters-cpp has a bunch of optional dependencies which allow building plugins with specialized converters within the same build system as the protocol buffer converter plugins.

Optional dependencies are suboptimal in themselves, but in this context, more problems arise:

• The OpenCV plugin forces the whole rst-converters-cpp project to be built against a specific OpenCV version
• The humavips and amarsi flavors of the project have caused countless headaches, especially for packaging
• RCI in particular, with its Eigen dependency, has further aggravated the problem (#2625)