Add axes for complex engine heat management

Currently the game offers only single command in controller settings for managing engine temperatures, a set of buttons for managing cowl flaps. In practice this command manipulates a control for engine air outtake on the Beechcraft Bonanza, which if opened causes more airflow through the engine cowling and hence running it cooler. The problem with this setup is that:

  1. You cannot bind axis to the control, even though these types of controls are particularly suitable for axes.
  2. It´s not exactly applicable for similar controls (notably oil cooler flap on Pilatus Porter), and is not in any case being used to work the control at the moment.
  3. Some types of aircraft, notably piston engine warbirds come with multiple controls for engine heat management, often two or three.

As such I´d recommend the following axes are added as options in controls options, under Instruments And Systems → Engine Instruments:

Engine Air Cooler Intake Axis
Engine Air Cooler Outtake Axis (this is what is currently operated as “cowl flaps” on the Bonanza)
Engine (Liquid Cooler) Radiator Axis
Engine Oil Cooler Axis (aside warbirds, present on the Pilatus Porter at least)

Split from: Add more support for axes in keybindings