Draft: Use a GCS bucket to deploy the review apps
Update the jobs for the review apps to use a deploy script (taken from https://gitlab.com/gitlab-com/www-gitlab-com/-/blob/master/scripts/deploy).
The following env variables are used and set at the project settings:
GCP_BUCKET_REVIEW_APPS
GCP_PROJECT_REVIEW_APPS
GCP_SERVICE_ACCOUNT_KEY_REVIEW_APPS
The jobs also use the https://hub.docker.com/r/google/cloud-sdk Docker image, which includes the necessary tools for Google Cloud.