[Patch] Prefer OAuth, provide authorization at upload

[malenki]

When one tries to upload from a blank JOSM installation one is asked for username and password and gets warned that both are transferred and (if selected) saved as plain text.

A hint to use OAuth or even the possibility to activate it from that dialog would be great.

[skyper]

See also #6171 and #7482

[simon04]

In 9352/josm:

fix #7612 - Prefer OAuth, provide authorization at upload

[malenki]

Thanks for solving this issue.
Just tested it: works like a charm. :)

[simon04]

In 9374/josm:

see #7612 - use basic authentication for unit tests