Add in metrics for Conntrack

[thompson-tomo]

Area(s)

area:system

What's missing?

Metrics defined for conntrack as used by host receiver https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/hostmetricsreceiver/internal/scraper/networkscraper/documentation.md

Describe the solution you'd like

Introduction of the metrics in semconv with *.max becoming *.limit.
Adding a utilization metric if the *.count metric is renamed to become *.usage given there is a defined limit/max.

Tip

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