Setup the payment module

The module includes all the setup to make payments for Android, iOS and Web using RevenueCat and LemonSqueezy. Including a trial and a paywall screens, services for RevenueCat and LemonSqueezy, and a payment function for each of those via WebHooks.

Under construction.

We will update it soon!

Main Flow:

1. Fetch products from RevenueCat or Firebase for web
2. Show a paywall screen
3. User purchases
4. Reveneuce Cat or LemonSqueezy SDK handles it
5. Returns results and UI is shown to user
6. WebHook is fired and Firebase is updated (user claims and store)
7. App refreshes user token and gets new claims.