title: How to get the details of the user deleted in keycloak using AdminEvent
body: <p>i have below code that gets executed when an admin is creating or deleting a user in the keycloak UI.
  Through the help of the adminEvent: <a href="http://www.keycloak.org/docs/3.0/server_admin/topics/events/admin.html" rel="noreferrer">http://www.keycloak.org/docs/3.0/server_admin/topics/events/admin.html</a>
  Creating a user returns the user details via adminEvent.getRepresentation().
  However when deleting a user returns me a null.</p>
  
  <p>This is also the same when deleting a role, deleting a group or deleting a user_session.(ResourceTypes)</p>
  
  <p>My question is how can i retrieve the deleted details?</p>
  
  <pre><code>import org.keycloak.events.admin.AdminEvent;
  import org.keycloak.models.UserModel;
  
  public void handleResourceOperation(AdminEvent adminEvent, UserModel user) {
  
          MQMessage queueMessage = new MQMessage();
          queueMessage.setIpAddress(adminEvent.getAuthDetails().getIpAddress());
          queueMessage.setUsername(user.getUsername());
  
          switch (adminEvent.getOperationType()) {
          case CREATE:
              LOGGER.info("OPERATION : CREATE USER");
              LOGGER.info("USER Representation : " + adminEvent.getRepresentation());
              String[] split = adminEvent.getRepresentation().split(",");
              queueMessage.setTransactionDetail("Created user " + split[0].substring(12));
              sendQueueMessage(adminEvent, queueMessage);
              break;
          case DELETE:
              LOGGER.info("OPERATION : DELETE USER");
              LOGGER.info("USER Representation : " + adminEvent.getRepresentation());
              queueMessage.setTransactionDetail("User has been deleted.");
              sendQueueMessage(adminEvent, queueMessage);
              break;
  }
  </code></pre>