FR: Ability to set the sensitivity and deadzone per joystick and per axis.

Quickest course of action would be to add the sensitivity and deadzones to a cmdline parameter, however some design considerations must be made.

Sensitivity and Deadzone are unique to the controller and axes per controller, however they can be individual preferences to players as some could prefer more sensitivity. Deadzones may also be player preference but its nature as artificial hysteresis to counteract mechanical issues tend to be constant to the device.

Conflict may arise with the usage of the `--deadzone` cmdline flag.