Create joy mapper node

[vexandmore]

Subtask of #634

Create a node which handles switching between control types and ideally controllers.

• Subscribe to /joy, and detect which controller is connected (PS4 controller in either of two mappings, Logitec joystick)
• Allow mode to be set (wheel, arm, arm ik) with a button (it contains this state)
• Publish to the four topics described in #632 (based on the mode)
• Be configurable with a yaml file (set which button and joystick axis corresponds to which motor)