Possibility to mark object as Favorite or Visited (and possibly add filters)

[andrisp]

Use cases:

• Mark object as Favorite when planning multiple object trip.
• Mark object as Visited to know which objects have been visited, so they could be filtered out.

Both features probably requires account creation, and storing user settings somewhere.
Or data could be stored in local storage but in this case all information would be lost when upgrading phone etc.