Add SEPA Payment Method Type

Let's postpone this on #2880160: Add Wero Payment Method Type, when we can finalize the best way to support these different sources with Stripe.

I'm aware about the Support iDeal through Stripe (sources) to prefer on a generic implementation of the different sources but i had recently the needs to use the SEPA debit source on a project and the quickest way to provides it was to re-use the initial work from the patch #1, so here attached the reroll of the patch with few improvements / fixes.

The patch #6 looks good. As the related issue #2880160 haven't got any progress since 4 years, it makes sense to commit the current patch.

@xavier.masson Is the SEPA payment usable with recurring payment (subscription) ?

Did someone manage to make this work for drupal 10?

The current patch works with rc6 but not for 8.x-1.1 version so I created a new patch here.
P/S: my mistake when the patch file is empty. Check next patch file please.

Because the Stripe Sources API has reached end of life, I have updated the StripeSepa payment gateway to use the Payment Methods and Payment Intents APIs.

If I understand correctly from #3408951: Refactor Stripe payment element for additional payment method types, the path forward for SEPA support is to implement a CommercePaymentMethodType plugin; thus this issue is no longer blocked. Based on that, I updated this issue's status and summary.

I just opened MR https://git.drupalcode.org/project/commerce_stripe/-/merge_requests/193, which makes use of the common superclass introduced on #3408951: Refactor Stripe payment element for additional payment method types. I've tested this locally with a Stripe sandbox:

• Prior to this MR, Commerce Stripe failed to process SEPA payments, logging the message The selected stripe payment method type(stripe_sepa_debit) is not currently supported..
• With this MR, Commerce Stripe successfully processes SEPA payments (the order transitions to the Completed state).

I rebased the MR, resolving the conflict by removing the update hook that was effectively identical to #3421392, under the assumption that this issue will also be part of the same tagged release as that other issue.

I performed the additional testing steps described in this comment:

1. anonymous and authenticated users ✅ — When a visitor completes checkout, the payment status is initially Authorization. Later, Stripe sends a charge.succeeded webhook request, and Drupal Commerce correctly updates the payment status to Completed.
2. Auth Only with Delayed Capture and Auth+Capture — n/a; SEPA does not support delayed capture.
3. Single Use vs Reusable ✅ — including reusing SEPA as a previously-saved on-session payment method
4. Refunds/Voids ✅ — When I refund the payment in the Stripe dashboard, Stripe sends a charge.refunded webhook request, and Drupal Commerce correctly updates the payment status to Refunded.
5. Behavior when cancelling the payment ✅ — After Stripe has notified Drupal Commerce that a payment has succeeded, if I click the Refund button on the payment in Drupal Commerce, Drupal Commerce updates Stripe to refund the payment

Based on that testing, I'll tentatively move this issue along to RTBC.

Unified the title