Add an option to use Cloud Run or COS as the Action runner

[ravwojdyla]

This is an idea suggested by Google engineer (Deok Filho), the idea is to leverage Cloud Run to execute the GitHub Action runner with the specific container (likely already with the code?). Cloud Run may have some instance size limitations, but maybe in that case we can use COS (Container-Optimized OS). See:

• https://cloud.google.com/run
• https://cloud.google.com/container-optimized-os/docs/how-to/create-configure-instance