MRP Kit Product logistics computation

When a product is a kit (a product whose bill of materials is of the kit/phantom type), Odoo normally has no real weight or volume of its own. This module makes those two values be calculated from the components listed in the kit's bill of materials.

• For each kit product, the module takes the first kit-type bill of materials found and adds up the weight (or volume) of every component, converted to the component's own unit of measure.
• The total is then divided by the quantity of the kit produced by that bill of materials, so the result is the weight/volume of one unit of the kit.
• If a product has several kit bills of materials, only the first one is used.
• The values are recalculated automatically whenever the bill of materials, its lines, the component quantities or the components' own weight/volume change.
• The fields stay editable: a user can still overwrite the calculated weight or volume by hand.

When the module is installed, all existing kit products are recalculated once, so their weight and volume are immediately correct.

It only affects the product variant screen (product.product) and its weight and volume fields; no new menus or screens are added. This matters for shipping and logistics, where correct weight and volume of kits are needed for carriers and delivery documents.