Mapview

- 36/41 - Fixes paths to icons
- 44 - missing markers in Kivy 2.0.0
- 40 - Crash if MBTilesMapSource used
- 50 - fix geojson linestring drawing

- API documentation migration

- Fix PyPI auto-deployment

- Genral code linting/cleaning
- Increase coverage testing from 14% to 35%
- Fix `Downloader` now checks for HTTP status code, refs 6

- Fix `AttributeError` on `GeoJsonMapLayer.canvas_line`, refs 12

- Migrate to kivy-garden/mapview