[EPIC][Pricing] : Improve priority management and compatibility between different promotion strategies

[RosaBenouamer]

→ As a merchant, I want the prioritization between multiple cart rules
to be clear
Today, we don't use the priority index defined in the parameters but the order of
but on the order of creation of the rule
Tomorrow: the priority index must be taken into account
→ As a merchant, I want the prioritization of the different rules affecting
the price is clear and configurable
Today, accessible on the product page in the "Pricing" tab →
Understand the impacts and the rule