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/Shader/Cache/Definition/HostShaderCacheEntryHeader.cs

@@ -0,0 +1,67 @@
+using System.Runtime.InteropServices;
+using Ryujinx.Graphics.Shader;
+
+namespace Ryujinx.Graphics.Gpu.Shader.Cache.Definition
+{
+    /// <summary>
+    /// Host shader entry header used for binding information.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Pack = 1, Size = 0x14)]
+    struct HostShaderCacheEntryHeader
+    {
+        /// <summary>
+        /// Count of constant buffer descriptors.
+        /// </summary>
+        public int CBuffersCount;
+
+        /// <summary>
+        /// Count of storage buffer descriptors.
+        /// </summary>
+        public int SBuffersCount;
+
+        /// <summary>
+        /// Count of texture descriptors.
+        /// </summary>
+        public int TexturesCount;
+
+        /// <summary>
+        /// Count of image descriptors.
+        /// </summary>
+        public int ImagesCount;
+
+        /// <summary>
+        /// Set to true if the shader uses instance id.
+        /// </summary>
+        [MarshalAs(UnmanagedType.I1)]
+        public bool UsesInstanceId;
+
+        /// <summary>
+        /// Set to true if this entry is in use.
+        /// </summary>
+        [MarshalAs(UnmanagedType.I1)]
+        public bool InUse;
+
+        /// <summary>
+        /// Reserved / unused.
+        /// </summary>
+        public short Reserved;
+
+        /// <summary>
+        /// Create a new host shader cache entry header.
+        /// </summary>
+        /// <param name="cBuffersCount">Count of constant buffer descriptors</param>
+        /// <param name="sBuffersCount">Count of storage buffer descriptors</param>
+        /// <param name="texturesCount">Count of texture descriptors</param>
+        /// <param name="imagesCount">Count of image descriptors</param>
+        /// <param name="usesInstanceId">Set to true if the shader uses instance id</param>
+        public HostShaderCacheEntryHeader(int cBuffersCount, int sBuffersCount, int texturesCount, int imagesCount, bool usesInstanceId) : this()
+        {
+            CBuffersCount  = cBuffersCount;
+            SBuffersCount  = sBuffersCount;
+            TexturesCount  = texturesCount;
+            ImagesCount    = imagesCount;
+            UsesInstanceId = usesInstanceId;
+            InUse          = true;
+        }
+    }
+}