Use Listxml serializer for reading only

SabreTools.Models/Listxml/M1.cs

@@ -0,0 +1,28 @@
+using System.Xml;
+using System.Xml.Serialization;
+
+namespace SabreTools.Models.Listxml
+{
+    [XmlRoot("m1")]
+    public class M1
+    {
+        [XmlAttribute("version")]
+        public string? Version { get; set; }
+
+        [XmlElement("machine", typeof(Machine))]
+        [XmlElement("game", typeof(Game))]
+        public GameBase[] Game { get; set; }
+
+        #region DO NOT USE IN PRODUCTION
+
+        /// <remarks>Should be empty</remarks>
+        [XmlAnyAttribute]
+        public XmlAttribute[]? ADDITIONAL_ATTRIBUTES { get; set; }
+
+        /// <remarks>Should be empty</remarks>
+        [XmlAnyElement]
+        public object[]? ADDITIONAL_ELEMENTS { get; set; }
+
+        #endregion
+    }
+}