Add support for associatedStreet address relations

[Nekzuris]

This tagging practice is controversial, but there are more than 5 million address numbers linked to a street by this relation in France, which currently only show as a number in OpenStreetBrowser like this

https://wiki.openstreetmap.org/wiki/Relation:associatedStreet
https://wiki.openstreetmap.org/wiki/Relation:street

[plepe]

This is currently not possible with the OpenStreetBrowser infrastructure. I can't promise you if this will ever work, but it might.

I'm also worried, that this would put some considerable additional load to the Overpass API server.