Update plugin for job queues

[mariusandra]

When 1.25 lands.

Closes #1

[mariusandra]

TODO: needs session_duration and possibly the event names to be reverted to the old style?

[mariusandra]

I just realised one thing. While this will definitely work most of the time, it definitely won't work when we're processing a backlog of a few hours. From the perspective of this plugin, that relies on scheduled jobs ("run this in 30min") and expiring redis keys, this will get be tricky.

The solution to this is to somehow add a session id into the cache key, and then a if (first tiem) { send event } else { check time between events and send end if needed } but I'm not yet exactly sure how.

Related: events with custom timestamps entered by the user (3 events in a row: t + 1 hour, t - 1day, t, t + 30min) will also cause issues.

[mariusandra]

Tested, works, merging.
The only problem is that this still expects to receive events in real time, so you'll get faulty sessions if batch processing a lot of things at the same time.