Feature (in the future): Add statistics logging for API

[zSleepwalker]

Statistics logging with URL, POST info, HttpStatus (2xx, 4xx, 5xx...) and frequency.
This will be useful in the future to add missing endpoints and remove endpoints that aren't used.

Right now it might not be needed, but in the future we might have endpoints built that no longer is in use.

[zSleepwalker]

Just an addition, could just be to expose the metrics under "/_/metrics".
These can then be picked up by things like Prometheus.

<metric-type-name>{<filter1-name>="<filter1-value>",<filter2-name>="<filter2-value>"} <current-value>

Example:

go_gc_duration_seconds{quantile="0"} 5.4603e-05
go_gc_duration_seconds{quantile="0.25"} 6.5151e-05
go_gc_duration_seconds{quantile="0.5"} 8.1182e-05
go_gc_duration_seconds{quantile="0.75"} 9.6932e-05
go_gc_duration_seconds{quantile="1"} 0.000167744
go_gc_duration_seconds_sum 0.191906531
go_gc_duration_seconds_count 2086