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.Gpu/GraphicsConfig.cs

@@ -32,5 +32,16 @@ namespace Ryujinx.Graphics.Gpu
         /// Enables or disables the Just-in-Time compiler for GPU Macro code.
         /// </summary>
         public static bool EnableMacroJit = true;
+
+        /// <summary>
+        /// Title id of the current running game.
+        /// Used by the shader cache.
+        /// </summary>
+        public static string TitleId;
+
+        /// <summary>
+        /// Enables or disables the shader cache.
+        /// </summary>
+        public static bool EnableShaderCache;
     }
 }