App: Day / night mode

It could be a new setting with options:

  • User
  • Sunrise / sunset
  • Day
  • Night
  • Light sensor

The User mode is default and works like now:
users select freely the map + display colors.

The other 4 options alternate between 2 predefined color sets.

  • Map: Normal (or High contrast?) and Dark color
  • Display: 2 predefined sets for Display / Icon / Font colors