If an addr:place is given but no addr:street tag, then bind
the rank 30 object always to a <=25 object, even when there
is none found with the same name.
Before updating an admin boundary we need to make sure that any
artificially generated 'linked_place' entry is removed from the
extratags column. This ensures that the place designation does
not linger when a linked place disappears and that it is updated
when the linking changes.
The initial search and address rank is saved in a table
that is set up from a json configuration file. Ranks may
be assigned on a country level according to class and
type of the object. Special handling that depends on the
geometry or OSM type is still hard-coded in placex insert.
The new default config file mimicks the current assignment
as close as possible. A couple of exceptions have been
removed, most notably the exception for Irish townlands.
