Checkout Button Schema

[gealcan]

What problem are you trying to solve?.
Allow the checkout button redirect link to be edited via site editor.
Today, this behavior is controlled by the prop finishShoppingButtonLink(editable only via code).

It's interesting to go directly to the last checkout stage to speed up the checkout process.
However, when there is gift promotion, the only place where the user can choose the gift is on the first checkout stage:

So it's useful for the commercial team to be able to change this behavior easily via site editor:
When there is a active gift promotion they would choose to send the user to the first checkout stage. Otherwise, they would choose the last checkout stage.

Describe the solution you'd like
Create a schema in this component so the redirect link can be edited via site editor

Related to #315