Add support for Google Pay

[jakubtobiasz]

This task aims to allow a customer to pay with using Google Pay. Below is a list of official guides on how to integrate Google Pay with web browser payments.

Ref:

• https://docs-api.tpay.com/pl/payment-methods/google-pay/
• https://developers.google.com/pay/api/web/overview
• https://developers.google.com/pay/api/web/guides/tutorial

Small wins 🏆

• [ ] Google Pay payment method can be added via Admin Panel
• [ ] Once Google Pay payment method chosen, the Complete button should be replaced with Google Pay's pay button*
• [ ] If a Google Pay payment success, the payment should show up as success
• [ ] If a Google Pay payment fails, the payment should show up as failed
• [ ] It should be possible to pay via API using Google Pay

Instead of the Complete button we should see: