Preferences: initial Preferences Activity, Provider and XML

Change-Id: I27d44993c4e34e08cfafff6d7a418df7c4f06fd2

Preferences: Hide search bar preference + others

- Restart Launcher on preferences changed
- Implement "getCurrentOrientation()"

Change-Id: I0728824ab994984c1dc798b61efa26b727ca3ea2

Move "System settings" to the bottom of the menu

Preferences: Auto-rotate screen

Change-Id: I126b57932bad994c3fcfa3c764d94bdb60037a93