Automatically propose devices that could be "known"

[AlCalzone]

trafficstars

Based on #26 we could detect frequently present devices (#29) and propose them to be added to the known devices list.

[lobomau76]

Proposing yes, but not automatically transforming to an "known" device. Perhaps something like if an unknown device has been detected x-times (where x should be defineable by user) it is proposed as known device. Between detecting there should also a gap of time, e.g. minimum 5min. between the detections, otherwise a person who walks by could be easily detected 6 times in a minute.

[AlCalzone]

Yes, I'll need a good metric for that. My first thought was having a state that determines if the device is present or not, and then using that presence state to decide if the device qualifies as known or not.