Unify control modes

[calebchalmers]

Currently, we have three options for robot control, depending on the state of the right switch on the controller:

• UP: Turret-relative joystick control (forward is the direction the turret is pointing)
• MID: Chassis-relative joystick control (forward is the direction the chassis is pointing -- opposite of the health bar)
• DOWN: Keyboard and mouse control (also turret-relative since the operator will be looking through the camera)

We can combine the keyboard controls with the joysticks, so that we don't have to switch back and forth when using the client. This would also allow drivers to use the controller, keyboard, and mouse simultaneously.