Add color mode setting

The new setting appears on devices that support color management
and wide color gamut rendering. The setting allows the user to
choose between natural (sRGB), boosted (sRGB + 10% saturation)
and saturated (unmanaged colors; colors are remapped to the device's
native gamut).

This change adds a metric constant for analytics in Settings
and uses a persistent system property to know when to suppress
color management.

Bug: 68159303
Test: manual
Change-Id: I83cc972fc3a2290ff106eae0e76a3ee799503813