Prometheus Metrics

[mohammed90]

Caddy can expose /metrics endpoint on the admin interface to support instance monitoring. The plan to add metrics for Kadeessh has always been there but didn't get around to adding them. Miek Gieben (miekg) has recently published a program that scrapes sshd logs for the ssh authentication metrics. Kadeessh can provide such metrics and more by having native support for metrics as it observes everything flowing in/out without having to scrape logs.

Decisions to be made about what metrics to collect/expose and how to wire the collection effectively.