Get robot-specific configuration via the ROS parameter server

[spmaniato]

Issue

Currently, the synthesis pipeline is configurable, but not via the ROS parameter server. The reason is that a single instance of the pipeline can handle any robot at runtime; the robot’s configuration isn't specified at launch. Python makes this easy since we can just import the corresponding module based on the contents of the action goal (specifically, the system field of the BehaviorSynthesisRequest message)

The main disadvantage of the current approach is that it means all relevant files have to be in specific locations/directories within the vigir_behavior_synthesis and ReSpeC packages. This goes against the ROS philosophy and various software architecture best practices.

Notes

• ReSpeC should still be ROS-independent after any changes.
• The configuration of each robot should be loaded under a corresponding namespace. For example, atlas/action_preconditions, create/action_preconditions, etc.
  • Think global and local costmaps.