Fixes#1066
This PR adds a new field `access` in the transportation layer, which will be set to `no` if the `access` tag is either `no` or `private`. While `private` is the more popular value by a 17:1 ratio, I went with `no` because it's smaller in the tiles. In addition, the text `no` opens up the future possibility of other text-based access values such as `destination`, `customers`, or `permit`.
The screenshot below shows an example of access tagging for a road on a military base:
To avoid discontinuous transportation lines between zooms 9 and 11.
- Originally limit geometry by length for z9 - z11 (`ST_Length(geometry) > ZRes(11)`)
- highway z9 to z11 was generalized during import-osm
- now just create a filtered and generalized z11 table
- then merge segments in the same way as from (full-featured) osm_highway_linestring and used this merged z11 for mat.view z10 and z9
Close#1107
