Feature: Select controller per sensor type

[rzr]

And use simulator by defaults, then I2C bus can be scanned to select the right controller (per address)

Relate-to: rzr/generic-sensors-lite#5

Feedback welcome, here or at:
https://discourse.mozilla.org/t/ds18b20-as-webthing/34111/5

[rzr]

An other option would be to add a combo box to select appropriate sensor

Relate-to: rzr/generic-sensors-lite#13

cc: @dror3go