Rename two targets to have SettingsLib prefix

- Rename lib name of ActionButtonsPreference and LayoutPreference.
- Remove Settings* prefix for directory name of LayoutPreference.
The LayoutPreference is in settingslib so it's pretty clear
it's a settings widget.

Test: Rebuild
Change-Id: I8f4b8643ee4b2cb3756d1c3e82d91021916e08c2
Fixes: 120706174