Title: Export Common Duration Metrics

Description:
With #33240 we got the ability to export various commonly used durations via access logs (thank you!!!). However, it would be great if there was a way to also export these as metrics so they can be ingested by Prometheus.

I don't have a specific design in mind right now, but anything that would pre-aggregate these durations would help immensely in ensuring we can easily alert on the performance of downstream, upstream and envoy itself.