These are used to mark large paved areas. Sometimes they exists
together with named regular streets. In such cases the unnamed
area may overshadow the actual street when computing the address
parent. As unnamed highways are not very useful anyway, we
simply remove them from the database.
Postal boundaries usually just have the postcode tag set and are
therefore officially 'nameless'. We want to have them as
boundary=postal_code anyways in order to distiguish them from postcode
points inherited from addr: tags.
Boundaries and places now always get a rank < 26 to make sure that
they do not parent to a street. Skip boundary=place completely
because they will be covered throught the secondary place tag.
Traffic signs rarely have name and are therefore mostly not
searchable. Remove them completely. Allow street lamps only when
they have a name. Removes about 2M object from a planet instance.
