Sale order line price history

On a sale order, each order line now shows a small history icon next to the unit price (in both list and kanban views of the order lines). Clicking it opens a pop-up called "Price history per customer" listing past sale order lines for the same product and customer.

The pop-up shows, for each past line, the order, the customer, the order date, the quantity, the unit price and the discount (discount only for users allowed to use discounts on sale lines). Two options refine the search: - Include quotations: also show draft and sent quotations, not only confirmed and done orders. - Include commercial entity: include the customer's parent company and its contacts (on by default).

Quotation lines appear highlighted. The number of past lines shown is limited by a system setting (20 by default).

Each history row has a check button that copies that old unit price and discount onto the current order line and closes the pop-up. The history icon is hidden once the line has been invoiced.

The module touches sale.order.line (adding the order's customer on the line) and adds two helper models, sale.order.line.price.history and sale.order.line.price.history.line, available to sales users.