feat(monitoring): adds an SLI for kube cluster scaleup events.
Add a service-level indicator for GKE Cluster Autoscaler scale-up events.
Once we've got a better idea of the values, we can add an SLO.
Snapshot: https://dashboards.gitlab.net/dashboard/snapshot/h4t4X1bpGsfY54nZWXTAxLYyDtVN7Okf
Edited by Andrew Newdigate
