0041769: Refactor Product Gift Card payment functionality to use WebPOS payments instead of negative lines

Description

Refactor Product Gift Card payment functionality to use WebPOS payments instead of negative lines.

The main objective of this development is to refactor the way Product Gift Cards are used when paying a ticket.
There are several countries in which the financial laws state that it is forbidden to have positive and negative lines at the same time in a ticket. The current gift cards implementation works by creating negative gift card lines to reduce the total amount of the ticket, virtually paying the ticket; this functionality is therefore not usable in countries with the mentioned laws.

With this development, gift cards will be used as normal payments within the normal receipt. Upon completing the receipt, two tickets will be created to consume the gift card according to the legislation: the first ticket will consume the entire gift card, and the second ticket will restore its remaining amount.

Steps To Reproduce

In an environment with Gift Cards configured, try to pay a ticket using a product-based gift card, and verify that a negative line is created.

Proposed Solution

Two main changes:
*Product Based Gift Cards will be paid using a payment method (same as credit notes and gift certificates)
*When completing a receipt paid with gift cards, one or two additional tickets will be created, transparently to the user: The first ticket will consume the gift card completely; the second ticket will restore the gift card balance to its remaining amount, if applicable.

Issue History
Date Modified	Username	Field	Change
2019-09-05 18:13	aaroncalero	New Issue
2019-09-05 18:13	aaroncalero	Assigned To	=> Retail
2019-09-05 18:13	aaroncalero	Triggers an Emergency Pack	=> No

Relationships [ Relation Graph ] [ Dependency Graph ]