Add device name preference in pairing page

Also refactor the preference controller
1. Extend from BasePreferenceController.
2. pass in the preference key. Then it could be reused in different
places with different key.

Bug: 69333961
Test: Screenshot | RunSettingsRoboTests
Change-Id: I773ca022baa326481045c1659565c9a21111200a
6 files changed