Make minimum landuse zoom levels more consistent

The minimum zoom levels are currently rather inconsistent. For example meadow
and farmland have a different minimum zoom level. This PR aims to improve this.

This PR lets all major landuse start at z10 (like most do already), except for
wood / forest. Smaller objects will start at z13.

Concrete changes in minimum zoom levels:

* tourism=camp_site, tourism=caravan_site, tourism_picnic_site from z13 to z10
* landuse=quarry from z11 to z10
* landuse=garages from z12 to z13
* landuse=farmyard, landuse=farm, landuse=farmland from z9 to 10
* landuse=village_green from z11 to z10
* natural=desert from z8 to z10 (solves partially #773)
* aeroway=apron, aeroway=aerodrome from z12 to z10
* highway=services, highway=rest_area from z14 to z10
Merge pull request #809 from math1985/landcover-minzoom

Make minimum landuse zoom levels more consistent