Calculating FIFO stocks.

[Dev-Int]

FIFO is First In, First Out.
When the choice of inventory calculation is 'FIFO', each invoice validation causes the registration of the price of each article.
Unlike the weighted price where the price is recalculated over the entire article, the FIFO price takes into account the quantity of each item and the price at which it is entered in the stock.
The application will have to save each price according to each storage date of the article.