Events API: returning past meetups

[sippis]

At this moment, API is returning yesterdays meetup when location is [Tampere](​https://api.wordpress.org/events/1.0/?location=Tampere)

Also duplicate appearance after meetup modification is visible here, as reported first time in #3027.

[iandunn]

IIRC, the endpoint intentionally returns events within a 24 hour window because timezones add extra complexity in determining when an event is in the past or not. I don't think we have a data source that maps lat/long coordinates to timezones, but there might be a good open source one out there.

We might be able to rely on the user's timezone that gets passed to the endpoint sometimes, but I don't think we'd be able to always rely on it.

[dd32]

IIRC The main issue with timezone support was that Meetup.com's API only returned timestamps in event local-time without any form of timezone specifier - so we'd require a city->TZ mapping on our side.

The Geonames data we're using does have TZ information too though which we could use for converting times