Get OSM auth working in lane editor

[dabreegster]

https://a-b-street.github.io/osm2streets/lane_editor.html is almost useful in real settings, but downloading the .osc file and opening in JOSM is an annoying step. Uploading to the API directly would be great.

I've started https://github.com/a-b-street/osm2streets/commit/750f958bcc12dde1fc39b37ac6bbe415c267d517 using https://github.com/osmlab/osm-auth, but I didn't get it to work. Forgot where I got stuck.

Just found https://github.com/NangoHQ/nango; maybe it can help?

Regardless how it's done, I'd love help on this one!