[SDK] Make snow effects configurable

There could be some settings for this in the airport editor/SDK so that each airport has it’s own settings with seperate options for Runway, Taxiway and Apron/Ramp snow clearances e.g. Something like this:

  1. No clearance (as it is now, and is correct for unmaintained small aerodromes/strips)
  2. Light clearance (less snow thickness/opacity(darker tarmac is visible through the snow, but only slightly) like for small aerodromes that are only occasionally plowed)
  3. Moderate clearance/streaky effect (like a large airport where it is plowed often but it often snows heavily)
    image
  4. Good clearance (like at a large international airport where it doesn’t often snow heavily)
    airport-runway-takeoff-airplane-flight-260nw-567632632

That way it could be set to mimic how that specific airport is cleared of snow in real life!

Discovered this SDK request, after posting in this other one: