Task: Add route exporting

If a user has built a route on your website, they need a way to actually navigate it in real life. The most valuable features here:

• Export to .GPX / .KML: So that the track with all unique points can be loaded in one click into Maps.me or Organic Maps (the main offline maps for travelers in Vietnam, where the internet frequently drops).
• Google Maps link generation: The ability to open the ready-made pool of points directly in the mobile Google app.