[gprd] Sping up a new k8s ratelimiting instance for gprd

Using the same general setup as in pre, create the redis ratelimiting instance in gstg.

A similar pattern was going to be used for redis-repository-cache, and those MRs are gitlab-com/gl-infra/k8s-workloads/tanka-deployments!483 (closed) and https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4046.