⚡ (billing) Automatic usage-based billing (#924)

BREAKING CHANGE: Stripe environment variables simplified. Check out the
new configs to adapt your existing system.

Closes #906





<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
### Summary by CodeRabbit

**New Features:**
- Introduced a usage-based billing system, providing more flexibility
and options for users.
- Integrated with Stripe for a smoother and more secure payment process.
- Enhanced the user interface with improvements to the billing,
workspace, and pricing pages for a more intuitive experience.

**Improvements:**
- Simplified the billing logic, removing additional chats and yearly
billing for a more streamlined user experience.
- Updated email notifications to keep users informed about their usage
and limits.
- Improved pricing and currency formatting for better clarity and
understanding.

**Testing:**
- Updated tests and specifications to ensure the reliability of new
features and improvements.

**Note:** These changes aim to provide a more flexible and user-friendly
billing system, with clearer pricing and improved notifications. Users
should find the new system more intuitive and easier to navigate.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/lib/api/pricing.ts

@@ -1,33 +0,0 @@
-import { env } from '@typebot.io/env'
-import { Plan } from '@typebot.io/prisma'
-
-export const priceIds = {
-  [Plan.STARTER]: {
-    base: {
-      monthly: env.STRIPE_STARTER_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_STARTER_YEARLY_PRICE_ID,
-    },
-    chats: {
-      monthly: env.STRIPE_STARTER_CHATS_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_STARTER_CHATS_YEARLY_PRICE_ID,
-    },
-    storage: {
-      monthly: env.STRIPE_STARTER_STORAGE_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_STARTER_STORAGE_YEARLY_PRICE_ID,
-    },
-  },
-  [Plan.PRO]: {
-    base: {
-      monthly: env.STRIPE_PRO_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_PRO_YEARLY_PRICE_ID,
-    },
-    chats: {
-      monthly: env.STRIPE_PRO_CHATS_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_PRO_CHATS_YEARLY_PRICE_ID,
-    },
-    storage: {
-      monthly: env.STRIPE_PRO_STORAGE_MONTHLY_PRICE_ID,
-      yearly: env.STRIPE_PRO_STORAGE_YEARLY_PRICE_ID,
-    },
-  },
-}