[TASK] Stripe backend tasks

[Mario-SO]

Description

Use the Stripe API to create and manage subscriptions from users

Related User Story

Related User Story #968

Objectives

• [ ] Create a webhook to listen for successful payments
• [ ] Update Org model with subscriptionTier and consumedHours fields
• [ ] Update Org model with channelPageAddon
• [ ] On org creation, set consumedHours to 0
• [ ] On successful payment, set subscriptionTier to the corresponding one
• [ ] On successful channelPageAddon payment, set the corresponding field to true

Acceptance Criteria

• [ ] Guarantee that NO user gets charged and not properly provided with account benefits
• [ ] Properly handle ALL possible errors stated in the stripe API docs

Additional Information

Stripe docs: Link

Subscription docs