Change building of the the request for the use case - don't use individual setters for payment data (amount, interval, payment type, iban, etc). Instead, build a PaymentCreationRequest and set it.

Remove all branching that checks the payment type of the returned donation (from the use case response). Instead, do the following:

• if the URL in the response is not null, redirect to it
• otherwise, redirect to the URL of the confirmation page.

Remove URL generators from the fundraising application repo (if possible, they might still be needed by memberships).