Fix colours and lighting from postprocessing and THREE.JS changes

[paulbrzeski]

Objectives:

• [x] Fix colours arising from postprocessing
• [x] Fix lighting from THREE.JS updates

[paulbrzeski]

• Langenium #33
  • Checking THREE.JS migration guides and release history for clues as to why colour grading is so whacked now, found the issue - https://discourse.threejs.org/t/updates-to-lighting-in-three-js-r155/
  • Tweaking colour values, shaders and light intensity to match existing Langenium look. Got most of the way there, I think the new look is better.
  • Removing stale references to old effects