With the PSD2 directive coming into effect on September 14th, it was time to switch our Stripe integration to use newer APIs that support Strong Customer Authentication (SCA for short).

This meant switching from the old stripe.js implementation for 'redirection' flow to the Stripe Checkout API and from the Charge API to the newer SetupIntent API for s2s flows.

This feature branch introduce these changes as well as some slight changes in the payment module (mainly functional improvement that were noticed when developing this, nothing major and no change in the flow/model of the basic payment models).

Note that the way our checkout flow is built for s2s transactions prevents us from using the PaymentIntent API (which would be a better fit that the SetupIntent in some cases) - to use that API, we would need the payment transaction to be created before the token, which is not the case in our current flows. This will probably be changed in a future task with a more flexible checkout flow.

In the mean time, the downside of using SetupIntent instead of PaymentIntent means that from the bank's point of view, the authorization of the card and the payment are 2 different requests - this could lead to a higher rejection rate in SCA flows and possibly to payments that stay 'pending'. There is no way to know for sure before PSD2 goes into full effect though, and this implementation should normally suffice.I would advise using the 'redirection' flow most of the time though, since it is clearly the best fit between Odoo and the Stripe APIs at the moment.

Task 1986267