Allow creating OpenStreetMap notes

[Robbendebiene]

Idea

Creating/Managing OSM notes from the app can have several benefits.

Use cases:

• Questions may not be answerable because the underlying OSM data is incorrect. Creating a note in such cases might be useful.
• Write "ToDos" to yourself or others that become apparent while being on sight
• Answer notes from others

Bug Relation

No response

Implementation

The osm_api already provides all necessary API calls.

• We could have an additional FAB button to create notes.
• We could have a toggle to switch between modes showing either questions or notes on the map.
• We could display notes similar to questions as markers.
• Questions or markers could have an option to write a note to this element. (note would be created at the same spot and may include some reference, like a name or id)

Additional Info

Writing a note doesn't require an OSM account. So this would be a way for people to contribute without having an OSM account (even though it would be a pretty small contribution).