Salieri: shader cache (#1701)

Here come Salieri, my implementation of a disk shader cache!

"I'm sure you know why I named it that."
"It doesn't really mean anything."

This implementation collects shaders at runtime and cache them to be later compiled when starting a game.

Ryujinx.Graphics.Shader/ShaderProgramInfo.cs

@@ -12,7 +12,7 @@ namespace Ryujinx.Graphics.Shader
 
         public bool UsesInstanceId { get; }
 
-        internal ShaderProgramInfo(
+        public ShaderProgramInfo(
             BufferDescriptor[]  cBuffers,
             BufferDescriptor[]  sBuffers,
             TextureDescriptor[] textures,