Persist a timestamp with events to the index

[jzonthemtn]

Persist a timestamp with events to the index. There is currently not a timestamp field for the events index.

[jzonthemtn]

This will require modifying the received JSON for events to add a timestamp field if none is included in the request. How this is done needs some consideration. I would like to have an object model for the events JSON and modify the event that way, but I'm not sure if that will accommodate the schema. Having objects would give easy access to the event properties. Using something like JSONObject is probably the easiest way though.

[jzonthemtn]

Implemented by using jackson JsonNode and ObjectNode to get the timestamp, if any, and set it to the current timestamp if not set.