add confirm setup to Stripe js

[cedvdb]

This effectively adds setup intent support for any kind of payment method on the web.

This adds ConfirmSetup to stripe web as confirmSetupIntent is deprecated. I used [ConfirmPayment] as a template to follow the conventions of this package.

This does not have test yet but was tested manually

[cedvdb]

The existing test failure seems unrelated to the changes here and a publishable key is not set in your infrastructure:

 IntegrationError: Please call Stripe() with your publishable key. You used an empty string.