Duration metrics not following Prometheus best practices

[hypery2k]

Bug Report

I was browsing the documentation on Proxy Metrics, and noticed some of the metrics don't follow Prometheus naming best practices. In particular this concerns the metrics regarding durations_

security_ssl_expire_days_remaining use base unit "seconds" instead of "days"

What is the issue?

Typically durations are described with the word duration within the metric name. (this one might just be personal taste, but it's the most frequently used and encouraged one one)
The metrics are not in base unit (seconds) but they are in milliseconds. This makes is difficult to work with various other component's metrics values as you need to convert to base unit.
Possible solution