Better logstash field data.

We are currently using a lot of wildcard searches in elasticsearch which
are slow. Provide better field data so that we can replace those
wildcard searches with filters. In particular add a short uuid field and
make the filename tag field the basename of the filepath so that grenade
and non grenade files all end up with the same tags.

Change-Id: If558017fceae96bcf197e611ab5cac1cfe7ae9bf
Merge "Better logstash field data."