Revise system metrics in opentetelemetry-instrumentation-system-metrics

[xrmx]

What problem do you want to solve?

Some system metrics captured in system-metrics instrumentations are out of spec.

Describe the solution you'd like

System metrics following the semantic conventions in system-metrics-instrumentation

Describe alternatives you've considered

We can wait for the semconv to become stable or we can introduce the metrics on a case by case basis.

Additional Context

No response

Would you like to implement a fix?

None