Switch to modern GCP Ruby Client

[pritho]

Currently the simple Rest client from https://github.com/googleapis/google-api-ruby-client is used in the backend.

Switch to the modern client for better performance, reliability and more features would be great: https://github.com/googleapis/google-api-ruby-client

From the Docs:
Google provides two types of Ruby API client libraries: simple REST clients and modern clients.
For most users, we recommend the modern client, if one is available. Compared with simple clients, modern clients are generally much easier to use and more Ruby-like, support more advanced features such as streaming and long-running operations, and often provide much better performance

(Created as a follow-up of #574)

[github-actions]

This issue has been marked inactive and will be closed if no further activity occurs.