Add Full system backup feature (#13945)

MediaBrowser.Controller/IServerApplicationHost.cs

@@ -38,6 +38,11 @@ namespace MediaBrowser.Controller
         /// <value>The name of the friendly.</value>
         string FriendlyName { get; }
 
+        /// <summary>
+        /// Gets or sets the path to the backup archive used to restore upon restart.
+        /// </summary>
+        string RestoreBackupPath { get; set; }
+
         /// <summary>
         /// Gets a URL specific for the request.
         /// </summary>