Data download metric for FDSN webservice

[nbalfour]

I would like to request a metric that tells me how much data has been downloaded from the FDSN webservice for any given month so that I can include it in our download statistics for the EQC quarterly report.

If this was available on webstats.geonet.org.nz that would be awesome but I don't really care where it is as long as I know where to look.

[junghao]

@nbalfour Started from Jul/2019, we have this metric available.