Goal: Use Google Workload identity Foundation (WIF) to authenticate to GCS bucket for image storage instead of long-lived, static credentials when using the GCS driver.

Background: Right now Quay is pushing images to the GCS bucket via HMAC keys and the request is to support Workload identity, so that authentication will be handled through short-living tokens.

Why this is important: Long-lived static credentials are considered insecure and bad practice and are increasingly prohibited in the enterprise space.

Required dependencies:

1. Implement GCP WIF configuration flow as described in PROJQUAY-7729

Acceptance criteria:

1. Allow configuration of GCS bucket auth to be 

https://cloud.google.com/iam/docs/workload-identity-federation
https://docs.openshift.com/container-platform/4.10/authentication/understanding-identity-provider.html