Bluetooth realistic example

[barbieri]

Similar to #732 we should have a realistic example for bluetooth where devices are discovered, paired and the pairing is persisted.

If possible sync with issue #732 so elements such as the selector could be reused. If there is no way to control BlueZ's persistence of pairing, then an option is to review OIC's and possibly offer an unified way that is similar in all p2p network protocols. In both cases the user still needs a way to select from a list of devices and select one to pair.