tracker-extract: Improve logging, too many debug statements

It was hard to see what was going on with most logs as debug comments.

Also all thread messages are now debug and have been moved into the #ifdef for
other thread events

It's a bit easier to see what is going on now using -v 2 and there is less
mess with -v 3
tracker-extract: Fixed epub extractor so it doesn't use broken ontology

- The nco:nameOther ontology doesn't exist. Now we use nco:nameAdditional
- The graph was not being used for inserts.
- The roles / affiliation were not inserted properly. WE now use artist
  (like other extractors)