Pay later option for customer orders (RTP-38295)

Pay later functionality enables customers to choose whether to pay the full amount upfront or split the payment into parts.
The new CustomerOrderPayLater parameter in POS Configuration determines whether the legacy order flow is used (CustomerOrderPayLater = False) or if it's replaced by the updated flow featuring the "Pay selected" dialog (CustomerOrderPayLater = True). The default value of this parameter is True. Orders follow proper flow in both cases, which includes updated order statuses, partial payments and due amounts. If POS Master and Chain Web-Backoffice aren't updated with the required versions, POS will automatically use the new order flow with the "Pay selected" dialog.