Point of sale - Search products by supplier

This module extends the Point of Sale product search so that the supplier information linked to a product is also taken into account.

• On each product, Odoo builds a technical text field that gathers, for every supplier listed on the product's vendor list, the supplier's name, the supplier's product code and the supplier's product name.
• This information is loaded into the Point of Sale session together with the other product data.
• In the Point of Sale screen, the product search bar now matches what you type against the supplier name, the supplier product code and the supplier product name, in addition to the usual product name and barcode.

It touches the product.product model (adding the computed supplier_data_json field) and the pos.session model (to include that field when loading Point of Sale data). No new menus, buttons, reports or scheduled actions are added; the change is only visible through the search behaviour in the Point of Sale interface.