Adds various rendering related fixes and tweaks.

* Fixes that the sky texture was completely black during the night
* Increases brightness during the night to compensate contrast changes introduced by the color grading lut
* Drastically improves volumetric fog rendering by sampling the skyband texture instead of a single color
* Increases blur factor for the skyband texture (so the clouds are not too obvious in dusty areas when looking towards the sky)
* Adds a new interpolated light value for the player position (smoothly updated over time so transitions between cells are smooth) which gets updated by the world renderer
* Adds that the volumetric fog effect gets disabled if the player stands in dark areas like trees (uses the new interpolated player light value to smoothen the appearance