add device profiles

since configuring device firmware completely by hand is rather error
prone, use device profiles instead. we now have profiles for several
devices used at the institute and elsewhere.

* Plug (relay)
* Plug+ (relay, power meter)
* EMOS sensor (temperature, humidity, 2 x PT100, buttons for windows)
* temperature sensor (temperature)
* humidity sensor (temperature, humidity)
* pressure sensor (temperature, pressure)

new profiles are easily added, and those that create firmware images
that have no associated profile are encouraged to do so.