Live/tail mode

[gak]

The ability to follow the latest log entries would be an awesome feature.

Due to the nature of Elasticsearch latency and ordering, the implementation needs to be considered. I'm leaning towards just showing logs in the order they are received from es.

• Poll Elasticsearch with an overlapping time frame, e.g. "everything in the last 5 minutes, order by timestamp.".
• If a log entry hasn't already been added, add it to the end of the entries.

The implementation is simple and should be fast, versus inserting log entries between older ones when they are out of order.

I think a prototype is needed to make sure this works reasonably, and potentially look at other options if it is jarring, slow, etc.