Stripe source: add `tax rates` stream

[btkcodedev]

Connector Name

source-stripe

❓ What

The Stripe connector does not sync tax rate information, which means the invoice_line_items are also missing information from tax_rates.

📈 Impact

Users can use the tax rate information in Stripe.

🤝 Proposed solution

Add a new stream tax_rates using the endpoint: https://docs.stripe.com/api/tax_rates/object This should also populate the field tax_rates on invoice_line_items (endpoint: https://docs.stripe.com/api/invoices/line_item)