Make sure technical alarms are raised

[mschottdorf]

I've never seen a blue box; maybe bug?

[mschottdorf]

I've done some digging:

In the pushed version, we update oxygen every 5 seconds, but should raise a stuck-sensor alert if a number doesn't change >0.2s [ this is prefs.get_pref('CONTROLLER_MAX_STUCK_SENSOR') ]. As it should, the controller is generating a warning, and logging it:

But no technical alert on the UI, so this might be a proper bug @sneakers-the-rat