[IDEA] Make PROP BETA writable

@FlyingRaccoon Have you guys had the chance to discuss this? it would be
really helpful. As per this Topic:
https://devsupport.flightsimulator.com/t/3479 Having the ability to write
this variable (even if we have to override it on each frame) would allow us to
do customs solutions much nicer. I am having to do some weird whichcraft at
the moment to move the beta angle on ground, which can have detrimental
effects to engine thrust, etc. The operation of almost ALL modern turbo props
engines requires this, it is how PT6 engines are designed, I checked the TBM
900 default airplane configuration and the Caravan, and they are also lacking
this capability despite of having a PT6 engine, so we would all benefit from
having new functionalities via this variable. And if you guys need any help, I
am more than willing to implement the “beta” operation range for the TBM and
Cessna Caravan so you guys can focus on something else, I just need more SDK
POWER to be able to do these things, please, please, please!! Best, Raul