allow locking UI mode and block launching car dock for automotive

- add config to lock UI mode change: When this is enabled,
  request to change car mode will be ignored. Apps can check
  the config using UiModeManager.isUiModeLocked()
- add config to lock day / night mode: When this is enabled,
  apps cannot change day / night mode without having
  MODIFY_DAY_NIGHT_MODE permission.
  Apps can check the config using UiModeManager.isNightModeLocked()
- add config to disable car dock intent launch for home key
  and mode change
- All new configs have default values which keeps the current behavior.
  Car products should override the configs to get desirable behavior.

bug: 22700993
Change-Id: Ic0e58f3428151e0b1c19a2e9a7d6ded32ff962a6