Also push reservation amount to datalayer when configured.
In some business cases, for example prepayment, when contact chooses payment method prepayment for their ticket (which they will pay it later), a reservation order will be created for this kind of payment. And in this case, the amount of the order is not push to datalayer, therefore, the report at Google Analytic is not accurate.
Getting started
A new key (config.datalayer.alsoPushReservationAmount) is introduced for each point of sales that allowing the operator to decide if the reservation amount should also be sent to datalayer.
