Autonomy Testing Environment in Simulations

[aerin-brown-codes]

The simulation is going to need to be revamped a little bit to allow for proper testing of autonomy. It'll need to have a variety of obstacles, ex. bushes, rocks of various sizes, shallow and steep hills, and cliffs approachable from above and below.

[aerin-brown-codes]

When we get the new URDF from mech (will probably be an incremental rollout--we'll get an incomplete one soon and a more accurate one later), this task will also be adding that in

[aerin-brown-codes]

There is apparently an old Mars terrain in some branch--investigate this.