implemented functions from NativeFunctions.cs

src-csharp/NativeFunctions.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Ougge;
+
+internal static class NativeFunctions
+{
+    [DllImport("__Internal")]
+    internal extern static void createGameObject(out ulong id, out uint index);
+
+    [DllImport("__Internal")]
+    internal extern static bool freeGameObject(uint index);   
+}