feat: add teams (#848)

## Description

Add support for teams which will allow users to collaborate on
documents.

Teams features allows users to:

- Create, manage and transfer teams
- Manage team members
- Manage team emails
- Manage a shared team inbox and documents

These changes do NOT include the following, which are planned for a
future release:

- Team templates
- Team API
- Search menu integration

## Testing Performed

- Added E2E tests for general team management
- Added E2E tests to validate document counts

## Checklist

- [X] I have tested these changes locally and they work as expected.
- [X] I have added/updated tests that prove the effectiveness of these
changes.
- [ ] I have updated the documentation to reflect these changes, if
applicable.
- [X] I have followed the project's coding style guidelines.

packages/ee/server-only/stripe/update-subscription-item-quantity.ts

@@ -0,0 +1,44 @@
+import type Stripe from 'stripe';
+
+import { stripe } from '@documenso/lib/server-only/stripe';
+
+export type UpdateSubscriptionItemQuantityOptions = {
+  subscriptionId: string;
+  quantity: number;
+  priceId: string;
+};
+
+export const updateSubscriptionItemQuantity = async ({
+  subscriptionId,
+  quantity,
+  priceId,
+}: UpdateSubscriptionItemQuantityOptions) => {
+  const subscription = await stripe.subscriptions.retrieve(subscriptionId);
+
+  const items = subscription.items.data.filter((item) => item.price.id === priceId);
+
+  if (items.length !== 1) {
+    throw new Error('Subscription does not contain required item');
+  }
+
+  const hasYearlyItem = items.find((item) => item.price.recurring?.interval === 'year');
+  const oldQuantity = items[0].quantity;
+
+  if (oldQuantity === quantity) {
+    return;
+  }
+
+  const subscriptionUpdatePayload: Stripe.SubscriptionUpdateParams = {
+    items: items.map((item) => ({
+      id: item.id,
+      quantity,
+    })),
+  };
+
+  // Only invoice immediately when changing the quantity of yearly item.
+  if (hasYearlyItem) {
+    subscriptionUpdatePayload.proration_behavior = 'always_invoice';
+  }
+
+  await stripe.subscriptions.update(subscriptionId, subscriptionUpdatePayload);
+};