[WIP] Lighting

[Strogoo]

This pr won't be merged in current state. As we discussed in Zulip giving that much control over sun color/position to UI may have some consequences. E.g. too many "fancy" clownlike presets shared via UI mods and then showed on streams, that may scare away new players and also upset mapmakers. So best thing we can do is make 4-5 presets (early morning, noontime, sunset, cloudy weather etc.) hardcoded in engine and then let user to switch between them.

For now all functions are available in UI, so we can find best values for presets which looks ok on common maps (like Setons, Gap etc). Ui functions:

    SetTerrainLightingMultiplier(float)  #Default value is usually 1.5-1.6
    
    SetSunColorRGB(r, g, b)
    
    SetSunPositionXYZ(x, y, z)         #Description below

Some examples on seton:

# Early morning

SetTerrainLightingMultiplier(1.8)
SetSunPositionXYZ(-80, 20, 10)
SetSunColorRGB(255, 255, 128)

# Sunset

SetTerrainLightingMultiplier(1.8)
SetSunPositionXYZ(60, 20, -20)
SetSunColorRGB(212, 64, 38)