Add a Nitro plugin to configure Stripe webhook

[beesoncaleb]

Description

The Stripe webhook that handles donations and storing them in the database has to be manually created on the Stripe dashboard. It would be better for this to be done automatically. You can read up on how to do that here

Acceptance Criteria

• Should check if the webhook already exists. Check for webhook with same destination and registered event.
• Should create a webhook if one exists, using env variable to determine destination
• Should be a nitro plugin