Stripe integration improvements

We've released a series of improvements to our Stripe integration, including failed payment notifications, enhancements to self-serve payments and an overhaul of our docs.

Here's what's new:

• We introduced new Stripe payment failure notification for merchants and end-customers to receive an email, instead of relying on Stripe's webhooks. When a payment fails, your customers can simply update their payment method via a new Stripe checkout link.
• We've updated our docs with set up recommendations, examples and frequently asked questions.
• Run a whitelabelled self-serve payment experience and hide Stripe payment links from invoices