Users should now use G_MESSAGES_DEBUG=Tracker to see debug messages
on the console.

The TRACKER_VERBOSITY only worked if tracker_log_init() had been called,
which can't be done when libtracker-sparql is being used from an
application outside of Tracker.

This also removes some little-used config utilities in the cli.
For `tracker reset --config`, you can instead use `gsettings
--reset-recursively`.