Switch auto time setting to use TimeManager APIs instead of low-level
direct settings access.
This makes the AutoTimePreferenceController approach the same as
AutoTimeZonePreferenceController. Most of the logic about what to
display and whether toggles are enabled is moved to the service.
This change has the side effect of adding support in SettingsUI for
devices with no auto time detection mechanism configured at all, i.e.
the auto time toggle will stop being shown in SettingsUI. There are no
known devices that require this currently, but it is a theoretical
possibility if config.xml is configured in particular ways.
Bug: 172891783
Test: Manual testing with different settings for "time origin
priorities" (i.e. empty, non-empty)
Test: m ROBOTEST_FILTER=com.android.settings.datetime RunSettingsRoboTests -j40
Change-Id: I4112fb51adb0d06a1dbc39a44ea109d6df899153
579a19a793