[Instrumentation.Runtime] Optimize options usage

[Kielek]

A bit odd. Why not just remove the parameter?

-public RuntimeMetrics(RuntimeInstrumentationOptions _1)
+public RuntimeMetrics()

Could make the whole class static. But need some way to make sure it is bootstrapped.

Like instead of...

        var instrumentation = new RuntimeMetrics(options);
        builder.AddMeter(RuntimeMetrics.MeterInstance.Name);
        return builder.AddInstrumentation(() => instrumentation);

Do something like...

        GC.KeepAlive(RuntimeMetrics.SomethingAccessibleToTriggetStaticCtor)
        return builder.AddMeter(RuntimeMetrics.MeterInstance.Name);

Originally posted by @CodeBlanch in #2281 (comment)