feat: add enterprise billing (#939)

## Description

Add support for enterprise billing plans.

Enterprise billing plans by default get access to everything early
adopters do:
- Unlimited teams
- Unlimited documents

They will also get additional features in the future.

## Notes

Pending webhook updates to support enterprise onboarding.
Rolled back env changes `NEXT_PUBLIC_PROJECT` since it doesn't seem to
work.

packages/ee/server-only/stripe/get-document-related-prices.ts.ts

@@ -0,0 +1,10 @@
+import { STRIPE_PLAN_TYPE } from '@documenso/lib/constants/billing';
+
+import { getPricesByPlan } from './get-prices-by-plan';
+
+/**
+ * Returns the Stripe prices of items that affect the amount of documents a user can create.
+ */
+export const getDocumentRelatedPrices = async () => {
+  return await getPricesByPlan([STRIPE_PLAN_TYPE.COMMUNITY, STRIPE_PLAN_TYPE.ENTERPRISE]);
+};