Allow enabling and disabling joystick messages
Sometimes people open multiple GCS and having more than one sending joystick messages will have unexpected behaviour, cockpit should have an option to disable joystick usage.
Fixed on #1339.
#1339 disables the entire joystick pipeline, which isn't the same as just disabling the messages sent to the autopilot - i.e. it also disables Cockpit Actions and data-lake variable modifiers, which a user may still want to use when they're not directly controlling the vehicle.
To better understand, why is this in the QGC equivalency project? It this functionality available there?
Nope - QGC just supports disabling inputs from the joystick (like described in #1311, and implemented in #1339), so not relevant to this specific Issue. I've removed it from the project to reflect that :-)