Refactor: Make the Notification not send themself but rather create their content

src/entities/SmsNotification.java

@@ -7,10 +7,4 @@ public class SmsNotification extends Notification {
     public SmsNotification(String content, User user, SendNotificationStrategy strategy) {
         super(content, user, strategy);
     }
-
-    @Override
-    public void send() {
-        if (isSendable())
-            strategy.send(user.id() + " Sms: " + user.name() + " " + content);
-    }
 }