Avoid query parameter to be mandatory

[karussell]

All columns not prefixed with expected_ should be able to provide an alternative to query. This way we can test geocoders with different query string parameters but also support reverse geocoding where just lat+lon is required.

(BTW: In this regarding specifying a different path before the ? of the URL would be handy that would replace the default forward geocoding endpoint.)

[yohanboniface]

Sounds legit. I'll have a look. It may have some backward tricks.