Compatibility module between sale_product_pack and website_sale

TT30385

Done for e-commerce compatibility purposes, althoug it's more performant
indeed.

Create and select a specific pricelist for avoiding problems in
integrated environments where the default pricelist currency has been
changed.

When the cart is confirmed, a price recalculation is triggered for every
order line. This is wrong for detailed totalized packs, which lines
should be at 0.

TT38186

…ts using packs