Add Device Information Service sample for bluetoothLowEnergy
bluetooth-samples/device-info-demo: Initial style changes.

Moved the Device Information Service sample into bluetooth-samples. Made minor
style changes and moved the UI logic into its own module.
Factured the bluetooth logic into a module.
Added screenshot
Merge pull request #268 from armansito/ble-device-info

Add Device Information Service sample for bluetoothLowEnergy