[New build - DEFAULT] 22w21a: Terrain Improvements

A follow-up on the terrain build.
Both performance and look have been greatly improved.

New Features:

• Terrain computation is much faster (from 30ms jobs to 3-4 ms)
  
• Job scheduling is also smarter. It will be noticeable when flying near terrain.
  
• Terrain loading is also optimized, for reduced FPS impact when moving near terrain.
  
• New textures added for rock, ground and ore.
  
• The new shader uses separate color gradient to prepare for a wider range of asteroids look / biome (for upcoming planet)
  
• Terrain will tesselate up close: the terrain will loom much higher resolution. It helps massively especially for rocks.
  
• Iron ore vein are being spawned.
  
• Terrain shadow added
  

Known issues:

• A lot of shadow artifact when new LOD are being loaded.
  
• A few issues with the border between different LOD. The current tech is not working well with tesselation, so it will be changed.
  

Thanks for playing!