Create overload for ToJson() with Formatting param

(cherry picked from commit aa2b0031671b6846eaa75e0914cd03ae7bbb0da7)

src/NzbDrone.Common/Serializer/Newtonsoft.Json/Json.cs

@@ -71,6 +71,11 @@ public static string ToJson(this object obj)
             return JsonConvert.SerializeObject(obj, SerializerSettings);
         }
 
+        public static string ToJson(this object obj, Formatting formatting)
+        {
+            return JsonConvert.SerializeObject(obj, formatting, SerializerSettings);
+        }
+
         public static void Serialize<TModel>(TModel model, TextWriter outputStream)
         {
             var jsonTextWriter = new JsonTextWriter(outputStream);