[WIP] Added a debug view system

[adriengivry]

Description

• Added a debug view system, including:
  • Albedo
  • Metallic
  • Roughness
  • AO
  • Normal
  • UV
  • Depth
  • Wireframe

Each debug view only applies to shaders declaring the associated pass (ALBEDO_PASS, METALLIC_PASS, etc.), except for the wireframe one, that can apply to virtually anything.

Related Issue(s)

Fixes #148

Limitations

• Increases the complexity of the standard shader (many new passes), however many of these passes could be useful for a future deferred pipeline
• Requires render features to be able to modify a drawable after it has been submitted (potentially poor design)
• Affect any pass (even picking/outline), which introduces visual artifacts

To-Do

• Add debug passes to the other shaders (unlit, atmosphere, skysphere)
• Implement a fallback solution if a debug pass doesn't exist on a custom shader
• Improve UI (toolbar)

Review Guidance

This needs more work to be viable.

Screenshots/GIFs

OvEditor_uur00DkGMp.mp4