code: protected Component newSigninPanel(final String id, final IModel<T> model)
  	{
  		final Component component = new SigninPanel<>(id, model);
  		return component;
  	}
docs: Factory method for creating the new {@link SigninPanel} that contains the TextField for the
  email and password. This method is invoked in the constructor from the derived classes and
  can be overridden so users can provide their own version of a Component that contains the
  TextField for the email and password.
  
  @param id
  the id
  @param model
  the model
  @return the new {@link SigninPanel} that contains the TextField for the email and password.