Implement NormalReconstructionPass

[vanruesc]

Description

Related: #722

Implement a NormalReconstructionPass that calculates accurate normals based on depth.

References:

• https://wickedengine.net/2019/09/improved-normal-reconstruction-from-depth/
• https://atyuwen.github.io/posts/normal-reconstruction/
• https://www.shadertoy.com/view/fsVczR

Tasks

• [ ] Create NormalReconstructionMaterial.
• [ ] Create NormalReconstructionPass.
• [ ] Add normal-reconstruction demo under utilities.
• [ ] Add unit test.

Implementation Details

• Implement material and use it in a new dedicated pass for normal reconstruction
• The pass should provide a texture getter for convenience
• Can use DepthDownsamplingPass as reference
• See #722 for reference