PW-243: isDuplicate now checks for the 'original_reference' field, this allows now to process two notifications with the same billing agreement but different payment.

#72 add refunded amount to adyen_order_payment table, fix multiple refunds on same pspreference for split payments, show split payments in overview payment information of the order and add column original_reference to notification table.

implemented authentication for notification, let the notification handler save the date so that timezone is correct, fix that live property is set in the notificaiton table and let the cronjob set notification to done when it is finished