fix(console): the console daemons log where the operator looks

- novncd and socketiod log to stderr: the journal on hosts, docker logs in
  the container (runit no longer sends them to unrotated files under
  /var/log). Django's settings gave them the panel's own log file, which
  every process rotated on its own, and made novncd's -v and -d have no
  effect; both work again.
- A refused console says why in the log: novncd's denials are warnings
  (they were shown only with -v), socketiod logs each refusal and who
  opened which VM's serial console.
- The README's serial console notes say what #228 changed (access
  re-checked, superuser takeover, reasons) and where the logs are.

console/tests/test_socketiod.py

@@ -91,8 +91,10 @@ class SocketiodTestCase(Base):
         self.assertEqual(self.started[0][0], self.d.forward)
 
     def refused(self, sid, auth):
-        with self.assertRaises(self.d.socketio.exceptions.ConnectionRefusedError) as refusal:
+        with self.assertRaises(self.d.socketio.exceptions.ConnectionRefusedError) as refusal, \
+                self.assertLogs("socketiod", level="INFO") as log:  # the reason is logged too
             self.d.connect(sid, {}, auth)
+        self.assertIn(refusal.exception.error_args["message"], log.output[0])
         return refusal.exception.error_args["message"]
 
     def test_refused_connections_start_nothing_and_say_why(self):