wip: upgrade stripe api

[alastair]

Issue(s) part of https://github.com/MTG/freesound/pull/1705

Description to upgrade to py 3.12 we need to upgrade stripe, but the API we were using is no longer supported.

We can no longer charge users an arbitrary amount. We need to create a product and a price. We still need to decide how we implement this in stripe - do we let users pick the price on the stripe site, or do we do it on freesound and dynamically create a price object?

With payment links, we can get payments from people without needing to first create a session from freesound, but we can't link additional data (credit name if they don't want their fs name).

In chat we discussed removing paypal and activating more payment types on stripe.

Deployment steps: