Stripe Payments - Add test mode

To test things and build automations we really need Heartbeat to offer us a test mode. Presumably by adding the option to add the Stripe test api key within Heartbeat and giving us the option Heartbeat to either run payment links over a test payment api key or live api key.

One of the issues right now is that it’s quite hard to build Pabbly automations, since Pabbly needs to catch a webhook first to build our automation on and we can’t trigger those without Stripe first firing it.

We either now have to first await paying members, and thus have to build the automations on a moving train. Or make real Stripe payments ourselves, which convolutes both Stripe and Heartbeat with unwanted data.