Refactor shader GPU state and memory access (#1203)

* Refactor shader GPU state and memory access

* Fix NVDEC project build

* Address PR feedback and add missing XML comments

Ryujinx.Graphics.Shader/IGpuAccessor.cs

@@ -0,0 +1,67 @@
+namespace Ryujinx.Graphics.Shader
+{
+    public interface IGpuAccessor
+    {
+        public void Log(string message)
+        {
+            // No default log output.
+        }
+
+        T MemoryRead<T>(ulong address) where T : unmanaged;
+
+        public int QueryComputeLocalSizeX()
+        {
+            return 1;
+        }
+
+        public int QueryComputeLocalSizeY()
+        {
+            return 1;
+        }
+
+        public int QueryComputeLocalSizeZ()
+        {
+            return 1;
+        }
+
+        public int QueryComputeLocalMemorySize()
+        {
+            return 0x1000;
+        }
+
+        public int QueryComputeSharedMemorySize()
+        {
+            return 0xc000;
+        }
+
+        public bool QueryIsTextureBuffer(int handle)
+        {
+            return false;
+        }
+
+        public bool QueryIsTextureRectangle(int handle)
+        {
+            return false;
+        }
+
+        public InputTopology QueryPrimitiveTopology()
+        {
+            return InputTopology.Points;
+        }
+
+        public int QueryStorageBufferOffsetAlignment()
+        {
+            return 16;
+        }
+
+        public bool QuerySupportsNonConstantTextureOffset()
+        {
+            return true;
+        }
+
+        public TextureFormat QueryTextureFormat(int handle)
+        {
+            return TextureFormat.R8G8B8A8Unorm;
+        }
+    }
+}