Robot State service instead of sending messages

[shawnhanna]

Instead of sending/updating the global planner's understanding of robot state via sending messages from robot to planner, we should use a service or some other way that will reduce/eliminate possible race conditions (ex: robot finishes task and receives a new task/cancellation at the same time).

If we use a service and update once per planning cycle, we will definitely reduce these issues, but still we should look more into this