implement new subscription dialog

[nucleus-ffm]

we need a new subscription dialog, based on a map to select places worldwide

subtasks

• [x] add map view
• [ ] add OSM nominatim to search for places or find a api where we can use auto completion
  • [x] create custom HTTP client with useragent
• [ ] implement loading screen
  • [x] first implementation
  • [ ] clean implementation
• [ ] add error handling