Per [this issue](https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/12542), we need to revisit our Cloud NAT IP routing. Steps: * [ ] Determine how we can expand the set of IP's to the Cloud NAT device - currently we apply a CIDR range and a count of IP addresses - the current allocated CIDR has no free IP addresses * [ ] Documentation updated to reflect how these are configured and how to expand in the future * [ ] Consider expanding our current Cloud NAT IP Allocation * [ ] Add saturation metrics for port usage