Implement a higher-quality anti-alisasing strategy

[adriengivry]

Problem this feature should fix

Overload's current anti-aliasing strategy (FXAA) is pretty blurry.

Expected solution

We should consider another approach, such as FXAA 3.11.

Requirements are:

• Single-pass, we should only update the FXAA shader
• Inputs should remain the same (_InputTexture)
• Performance shouldn't degrade too much
• The game should look less blurry