Allow per display level private flag control for physical secondary displays

- Deperecate config_localDisplaysPrivate which enables private flag for all
  secondary displays.
- Private display should be listed in config_localPrivateDisplayPorts array
  with port address to be marked as private display. Secondary displays not
  listed will remain as public displays.
- Use case: In env like car, display like instrument cluster should be only
  allowed to trusted system apps (=private display) while other non-main
  display like non-passenger side display can be accessed by 3rd party apps
  (=public display). This CL allows selectively enabling private display flag.

Bug: 131113705
Test: Run added tests
Change-Id: I60c4b6e3b2c9c841da7986c084593c530eb817bd