Procurement Purchase Service No Grouping

This module works together with the 'No order grouping' option in product categories and the sale-to-purchase link. It changes how service products are purchased when a sales order is confirmed.

• For service products whose product category has the procurement grouping set to 'order' (meaning no grouping), each sales order line generates its own purchase order.
• The module prevents Odoo from searching for an existing purchase order to add the line to; instead, it forces the creation of a new purchase order for each line.
• This behaviour is triggered automatically when a sales order is confirmed and the service product needs to be purchased.
• It only affects service products; other products follow the normal grouping rules.
• The module extends the purchase.order model to adjust how purchase orders are searched, and the sale.order.line model to change how service purchases are created.

No new menus or screens are added; the change happens behind the scenes during order confirmation. The result is that users see separate purchase orders for each sales order line when the 'No order grouping' option is active, which can help with tracking and receiving.