Cluster Monitoring++

With a foundation of Kubernetes cluster monitoring available in https://gitlab.com/gitlab-org/gitlab-ce/issues/38783, we can begin to take this further.

A few key enhancements we should consider:

• Display Mode health, capacity
• Display Pod status, capacity
• Include additional series for Limits for Memory/CPU. (In addition to utilization and Requested)
• Alerting in the event of errors:
  • Pods/Nodes at capacity
  • Flapping pods (can't authenticate to registry, bad container image, etc.)
  • Node errors
  • etc..