Clean up unused redis configs

After migration from redis sentinel to cluster, some ruby class(es) referencing the redis clusters were removed but we still have corresponding configurations in our setup e.g. redis_rate_limiting_(cluster_nodes|username|password): https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/blob/master/roles/gstg-base.json?ref_type=heads#L833-872

This issue is to identify and remove configurations similar to mentioned above.