Index additional fields

[mrdavidlaing]

We are currently only indexing the @message field.

Several users have been (rightly) surprised that not everything is indexed; after all it is a "search engine"

Now that we're getting the cluster perf problems under control I think its time to start indexing everything.

[dpb587]

Let's start with this (from @mrdavidlaing):

• host (e.g. ppe-*)
• message (not @message)

[dpb587]

For indexing additional fields, go ahead and open a new issue.