Context :
We want to implement some counters to monitor server health. First
counters will track : messageChannel sync status during job execution
and invalid captcha.
How :
Counters are stored in cache and grouped by one-minute windows.
Controllers are created for each metric, aggregating counter over a
five-minutes window.
Endpoints are public and will be queried by Prometheus.
closes https://github.com/twentyhq/core-team-issues/issues/55
