Record TimeZone in Geo data

[stephen-soltesz]

The geoip2.City struct includes a TimeZone field.

We should verify whether that value is actually present and save the timezone data with the location struct. This value is helpful for presenting results with local time-of-day.

If the TimeZone data is not in maxmind, then this becomes a tougher problem.

[pboothe]

P1 if this data is in MaxMind, P2 or P3 if it's not there.

[pboothe]

Server can do SiteInfo

[pboothe]

TimeZone offset of the server might be useful as well.