restrict size of features that get a full address search

restrict size of features that get a full address search

It would be nice to always compute addresses for rank 0 objects
over the complete geometry, so that they can be found via all
the admin boundaries that they intersect. However, there are a
couple of extramely large boundaries in OSM (like timezones)
where this results in thousands of possible address candidates
that need to be checked. Fall back to getting the address of the
centroid for them.