When a place of rank 30 has addr tags that are not covered by the
search terms of the parent, add a separate entry for the POI in
the search_name table that includes the addr tags. We can only
do that with named places. For POIs without a name the housenumber
is used as name. If that is not available either, searching still
won't work.
It may happen that two different postcodes normalize to exactly
the same token. In that case we still need two different entries
in the word table. Token lookup will then make sure that the correct
one is choosen.
Fixes#1953.
Always add contents of addr:* tags into address part of the search
table, even when there is no corresponding other name. This keeps
search tolerant to the kind of tagging where parts show up in the
address that have no corresponding object in the database or where
it is only an unaddressable object.
