Promotheus extension doesn't work with Windows

[CecileRobertMichon]

We should

1. Add validation to error if user tries to deploy an extension on windows that isn't supported (short term)https://github.com/Azure/acs-engine/blob/d0fbe11d334e9c90efceaaf39c1e304e471652d8/pkg/api/vlabs/validate.go#L1024

2. See how we can extend what is there for Linux to Windows (long term)

[PatrickLang]

This refers to https://github.com/Azure/acs-engine/tree/master/extensions/prometheus-grafana-k8s

Looks like most node metrics come from https://github.com/prometheus/node_exporter

[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.

[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 contributions.