Feat: Created up/down tilt for arms control

[ExoPrisma]

Description
  Added implementation of up/down tilt by taking the current pose and computing a new pose with a modified pitch (up or down) and returning the pose after IK.

Issues

• Increment of pitch might not be the most optimal way.
• Naming of button (3 for L2 and 4 for R2) might not be optimal.
• Might need to recheck clamping to make sure that the joint taken is the right one.

Assumptions

• Assume that value is normalized between -1.0 and 1.0.
• Assume that L2 points down and R2 points up (relative to the current orientation).

Code has not been tested yet

[aerin-brown-codes]

This looks good to me, but since Euler angles get pretty complicated, I'd like it if you added a couple unit tests in the test file. For example, test what happens when you give input at the limits. Also do a general case test by running the new angles through forward kinematics to make sure you're still getting the position you would expect (i.e. the hand_pose you're passing to the IK). That way we can make sure changes are as expected and no weird Euler angle stuff is causing IK to break down before we do sim testing.