Get alias for Bluetooth devices.

Bluetooth devices can be renamed by the user.  Make the
input system aware of the user-specified name and transparently
pass it down to applications.  This enables the keyboard
layout picker Settings UI to use device names that are
consistent with what the user set in the Bluetooth UI.

Bug: 6363157
Change-Id: I8eea26ce2c69c2a3f09c8de02e9e847610e0419c