Bug 905606 - Gaia for bug 892212 Support for BT inline pairing User

According to UX spec., the patch is supporting for Bluetooth inline pairing user story.
https://bugzilla.mozilla.org/show_bug.cgi?id=892212#c13
* Remove custom value selector(older paired devices list)
* Add device list component which is almost same with settings app::bluetooth(without toggle bluetooth, visible, and rename device's name)
* There is a workaround for waiting bluetooth protocol channel ready.
  * https://github.com/mozilla-b2g/gaia/pull/12069/files#L0R275
  * We will remove the workaround once "Bug 915602 - [Bluetooth] Call sendFile api will crash the system while device is just paired." is fixed.
* There is no 'bluetooth-pairing-request' system message callback in the first time, if we use bluetooth inline pairing.
 * Track: Bug 915611 - [Bluetooth] Cannot receive 'bluetooth-pairing-request' system message callback in the first time, if we use bluetooth inline pairing.