[FIX] point_of_sale: Split bill
[FIX] point_of_sale: Split bill

Clean code and make overrides easier.

X-original-commit: 73f71ac673a4174e3bfc2b3b441b7097f939742d
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo