KIP-386 — Standardize on Min/Avg/Max metrics' default value

Accepted Kafka 2.2 Metrics

Changes the default value of Kafka's `Min`, `Avg`, and `Max` JMX metrics from `-Infinity`/`NaN`/`+Infinity` to `-1` (or another well-defined sentinel) when no samples have been recorded. Third-party monitoring systems (Prometheus, Datadog) cannot handle `NaN`/infinity values and either crash or produce misleading alerts on a freshly started broker.

Details