⚡ (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 -->

.github/workflows/check-and-report-chats-usage.yml

@@ -0,0 +1,30 @@
+name: Check and report chats usage
+
+on:
+  schedule:
+    - cron: '0 * * * *'
+
+jobs:
+  send:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./packages/scripts
+    env:
+      DATABASE_URL: '${{ secrets.DATABASE_URL }}'
+      ENCRYPTION_SECRET: '${{ secrets.ENCRYPTION_SECRET }}'
+      NEXTAUTH_URL: 'http://localhost:3000'
+      NEXT_PUBLIC_VIEWER_URL: 'http://localhost:3001'
+      TELEMETRY_WEBHOOK_URL: '${{ secrets.TELEMETRY_WEBHOOK_URL }}'
+      TELEMETRY_WEBHOOK_BEARER_TOKEN: '${{ secrets.TELEMETRY_WEBHOOK_BEARER_TOKEN }}'
+      SMTP_USERNAME: '${{ secrets.SMTP_USERNAME }}'
+      SMTP_PASSWORD: '${{ secrets.SMTP_PASSWORD }}'
+      SMTP_HOST: '${{ secrets.SMTP_HOST }}'
+      SMTP_PORT: '${{ secrets.SMTP_PORT }}'
+      NEXT_PUBLIC_SMTP_FROM: '${{ secrets.NEXT_PUBLIC_SMTP_FROM }}'
+      STRIPE_SECRET_KEY: '${{ secrets.STRIPE_SECRET_KEY }}'
+    steps:
+      - uses: actions/checkout@v2
+      - uses: pnpm/action-setup@v2.2.2
+      - run: pnpm i --frozen-lockfile
+      - run: pnpm turbo run checkAndReportChatsUsage