v2.5.0: Prometheus is now supported!

Major new feature of this release is the addition of Prometheus support with the integration of the prometheus-cpp client library into cmonitor_collector.
cmonitor_collector is now able to expose, using --remote=prometheus option, an HTTP endpoint that can be scraped by Prometheus and will provide all stats about the system/container under monitor.

Thanks to @satyabratabharati for this contribution!