feat: added notification pattern (#2629)

Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>

notification/src/main/java/com/iluwatar/DataTransferObject.java

@@ -0,0 +1,16 @@
+package com.iluwatar;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+/**
+ * Layer super type for all Data Transfer Objects.
+ * Also contains code for accessing our notification.
+ */
+@Getter
+@NoArgsConstructor
+public class DataTransferObject {
+
+  private final Notification notification = new Notification();
+
+}