Start creating Dictionary-based internal models

SabreTools.Models/Internal/Original.cs

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+using System.Xml.Serialization;
+using Newtonsoft.Json;
+
+namespace SabreTools.Models.Internal
+{
+    [JsonObject("original"), XmlRoot("original")]
+    public class Original : DatItem
+    {
+        #region Keys
+
+        /// <remarks>string</remarks>
+        public const string ContentKey = "content";
+
+        /// <remarks>bool</remarks>
+        public const string ValueKey = "value";
+
+        #endregion
+
+        public Original() => Type = ItemType.Original;
+    }
+}