Move ROS 2 omnigraphs to a different layer #34
Description
Summary
Currently the Andino robot USD file contains all the omnigraphs in charge of handling ROS 2 communication. It would be great if we could split those omnigraphs into a different USD file, create an andino base file with the robot description only and add a sublayer that contains all the ROS 2 omnigraphs. That way we separate the actual robot from the communication layer/implementation.
This would be similar to how the Andino and Andinog_gazebo files work. The Andino Gz includes the base Andino description (Gz agnostic) and adds Gz specific logic on top.