Date detection on JSON fields

[PSeitz]

JSON fields include type detection for numerical types on columnar (not sure about the term dictionary).

It would be nice to add date detection to it. This should probably have a list of date formats to try. Ideally it could be restricted to some paths in the JSON object, since that can be expensive.

IP Fields could be handled similar (although they are less important)

[PSeitz]

When the JSON field contains timestamps, we could support date aggregation queries on it, when the user could define the precision in the aggregation API. That would be a extension of the elastic search API