Pixelated lighting features

[Junder-2]

Added pixelated shading using texel screenspace offsets. Tried to make it as contained as possible only modifying existing code when necessary. Options for applying it on shadows, vanilla AO, light, normals and on water reflections. Pixel scale option is shared.

Notes:

• Has small artifacts at far distances but only really noticeable when using a zoom mod.
• Light snapping causes stairs to have diagonal seam artifact, unsure why but mostly noticeable at max pixel scale.
• Normals are a separate option as it has artifacts and only effects a few surfaces such as water with waves. Up to you if it's necessary.
• Water reflections only get partially pixelated. Fairly subtle, up to you if it's necessary.
• Old pixel shadows are still left, being ignored if pixel shading is on. Up to you if it should be kept.

Shadows at pixel scale 1 Light and AO at pixel scale 2 Co-Authored-By: @Nestorboy

[Junder-2]

contribution is out of date, moved target to main just to make diffs clearer

[Nestorboy]

The settings that are currently exposed are as follows, but the user might want more or less control. It might also be worth merging the "Pixelate Shadows" feature into these settings or replace it entirely.

What are your thoughts @EminGT?