Alexander Reelsen 01e8eaf181 Date Parsing: Add parsing for epoch and epoch in milliseconds
This commit changes the date handling. First and foremost Elasticsearch
does not try to convert every date to a unix timestamp first and then
uses the configured date. This now allows for dates like `2015121212` to
be parsed correctly.

Instead it is now explicit by adding a `epoch_second` and `epoch_millis`
date format. This also means, that the default date format now is
`epoch_millis||dateOptionalTime` to remain backwards compatible.

Closes #5328
Relates #10971
2015-06-03 18:07:47 +02:00
..
2015-01-26 09:14:17 -08:00