Settings: Add Advanced reboot (1 of 2)

This commit adds a setting in Development settings for including options
in the power menu for rebooting into recovery or bootloader, defauled to
off.
When enabled, the Advanced reboot options will only be available once the
device is unlocked.

Change-Id: I202bf2adec3ba50c1a2e4de2a8f62cdad970ce04
Merge "Settings: Add Advanced reboot (1 of 2)" into lp5.0