* Drop obsoletely `node_cpu` metric recordings.
* Drop `CPUOutlierDetectionOnPrd` that doesn't work due to missing
recordings.
* Add new 1m rate recordings, with a 1m interval.
* Move CPU alerts to new metrics.
* Drop environment filter from CPU alerts.
* Drop 80% CPU threshold for "High CPU" to avoid alert noise.
* Move old 5m alerting to separate rule group.