Create and use DosCenter serializer

SabreTools.Models/DosCenter/MetadataFile.cs

@@ -0,0 +1,18 @@
+namespace SabreTools.Models.DosCenter
+{
+    public class MetadataFile
+    {
+        /// <remarks>doscenter</remarks>
+        public DosCenter? DosCenter { get; set; }
+
+        /// <remarks>game</remarks>
+        public Game[]? Game { get; set; }
+
+        #region DO NOT USE IN PRODUCTION
+
+        /// <remarks>Should be empty</remarks>
+        public string[]? ADDITIONAL_ELEMENTS { get; set; }
+
+        #endregion
+    }
+}