Create a new monitor/ subdirectory and move monitor.c there. As the plan
is to move the monitor core into separate files, use the chance to
rename it to misc.c.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190613153405.24769-8-kwolf@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>