Currently OpenTelemetryMetrics reports metrics with names inherited from the Prometheus integration.

We should adjust this to conform to the recommended naming as specified by OpenTelemetry docs.

Moreover, alongside the metrics, we should report the required attributes; if optional attributes are feasible and make sense, they should be included as well.

Strict binary/source compatibility is not required, however we should aim at keeping the changes to the necessary minimum, as well as documenting migration path.