Hex's Default Shaders Rewrite

The shader was not fully rewrited, some functions are still here.

Updates GHub

• Fully Working on Iris 1.6.17+.
• Fixed Most of the SkyLight leaks in Night time, at the cost of no Shadows at night time! (More info on Github.)
• Fixed somethings in shadows, added more shadows samples and smthings.
• Removed Bloom and Volumetric Lights.
• Added more gamma correction.
• Lights are now brighter.
• Testing for SSR and Custom lights in nether on version 0.8Alpha.