Start adding currently-unused models

SabreTools.Models/SoftwareList/DiskArea.cs

@@ -0,0 +1,15 @@
+using System.Xml;
+using System.Xml.Serialization;
+
+namespace SabreTools.Models.SoftwareList
+{
+    [XmlRoot("diskarea")]
+    public class DiskArea
+    {
+        [XmlAttribute("name")]
+        public string Name { get; set; }
+
+        [XmlElement("disk")]
+        public Disk[]? Disk { get; set; }
+    }
+}