Move all g_debug to TRACKER_NOTE
Right now some debug logs are gated behind
G_MESSAGES_DEBUG and others behind
TRACKER_DEBUG. The latter is more flexible so use that everywhere and avoid
g_debug(). (We'll still use g_message(), g_warning() and g_error() as those are not gated behind an environment variable).
We might be able to do this by modifying our log handler, rather than changing 200 instances of g_debug().