Add optional procedural normal map to Light Layer 3D

I added another parameter to Light Layer 3D which creates a procedural normal map of the texture which can be combined with a normal map generated from the depth.

When set to 0, it has no effect, as you increase it between 0-1, the texture also begins to work as an ad-hoc normal map (changes based on color changes of the texture). It can add a little 'roughness' to the faces of textures.

Example (turning off an on)