Remove NSSM and use kubelet.exe and kube-proxy --service flags instead

[PatrickLang]

Is this an ISSUE or FEATURE REQUEST? (choose one):
Issue - Kubernetes 1.10 won't need NSSM as a service wrapper for the kubelet or kube-proxy any more. See kubernetes/kubernetes#60144

The new flow would need to update setup windows script to register service as kubelet.exe --service ... using sc.exe or PowerShell new-service cmdlet

What version of acs-engine?:
v0.13.1

Orchestrator and version (e.g. Kubernetes, DC/OS, Swarm)
Kubernetes

[PatrickLang]

This isn't blocking - feel free to assign to me. Would be a good exercise as I ramp up on acs-engine

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution. Note that acs-engine is deprecated--see https://github.com/Azure/aks-engine instead.