QS: Introduce bluetooth control panel.

- Factor out common detail item panel view, share with Wifi.
- Add an empty state (large icon + text)
- Implement connect / disconnect for supported BT profiles.
- Wire up "scanning" state, but still waiting on asset.
- Add BT controller info to dump.

Bug:16235253
Change-Id: Icf854cafba962fe4b63767d7206e309d80b7b87b