Gift cards. Better support for multi currency.

[DB-TORGA]

nopCommerce version: 4.4

Steps to reproduce the problem:

Gift card notification email is always generated and send to customer using nopcommerce store base currency and base currency amount.

This can confuse webshop customers, for example customer buys a EUR 100 gift card, but customer recieves an email showing amount USD 110 .

Idea to fix the problem: in GiftCard table , add new columns for GiftCard.OriginalPurchaseCurrency and GiftCard.OriginalPurchaseExchangeRate.

Then the Gift card notification email can be generated using GiftCard.OriginalPurchaseCurrency and value as GiftCard.OriginalPurchaseExchangeRate x GiftCard.Amount