Collision model update for palm and forearm

To avoid self-colliding palm was updated so that thumb does not collide with palm. More box added but still simpler to check than a thousand-face mesh.
The wrist mount was not covered by a collision object, this means a planning algorithm would accept to penetrate the between the forearm and the wrist joint. A box was added to the forearm (different box for muscle and motor to cover the mount and avoid self collision with the palm.

used sr_description/test/tests_hand.sh to verify each existing model for consistency with new collision model
started simulated hand in gazebo and no collision or vibration observed.