Add support for Windows Containers

[Rob-B-NAIT]

We have Windows based worker nodes in our K8S clusters running Windows containers - it would be great if KRR also worked with the metrics that are output from the prometheus windows_exporter.

This might be as simple as using 'windows_container_cpu_usage_seconds_total' in place of 'container_cpu_usage_seconds_total' and 'windows_container_memory_usage_commit_bytes' in place of 'container_memory_working_set_bytes' though there are possibly other differences that I've not considered to complicate things.

Stretch-goal - support both sets of metric names in parallel, so I get a single report output with all of the containers in the cluster regardless of what OS they're running on.

FYI - the full list of windows container metrics is available here: https://github.com/prometheus-community/windows_exporter/blob/master/docs/collector.container.md

[aantn]

Hi @Rob-B-NAIT,
We are open to PRs for this and I'd be happy to point you in the right direction. Would you be interested in giving it a shot?