Implement date intervals in the rule engine

[romainruaud]

Todo after #3256

Having dates in the rule engine will not be very useful because it will require users to contribute conditions like :

• created_at "is greater than" "2024-01-01"

So they'll not be able to create dynamic rules like "product created in the last X days".

We should create these kind of rules as an implementation of Special Attributes, like we made previously for the "only grouped products", "only configurable products", etc...

My proposal is :

• Products created in the last X days (where X is contributed in the rule engine) : will be based on created_at attribute.
• Products updated in the last X days (where X is contributed in the rule engine) : will be based on updated_at attribute.

This will require to have a setup that will set the created_at/updated_at attributes to be "used_for_promo_rules=1".