Remove road properties at zoom 14 and 15

[nvkelso]

Following up from issues like #2019, #2017, and #1998, there is more opportunity to reduce the size of 512px zoom 13 and 14 tiles by dropping more properties to include more feature merging.

For example, in 512px tile 13/4093/2723.mvt we still see properties for "networks" both driving, transit, walking, and cycling when at these zooms there is probably not room to label those onto the map given the scale. We should keep enough properties so the line can be styled (eg that it is bike or is bus related), but we don't necessarily need to still include the operator or shield information.

This is partly based on the road class (or the network class), and partly based on the length of the road segment.

[nvkelso]

Depending on the size savings... we can also investigate adding config for dropping some of the non-driving info all together (which would be a breaking v2 change covered in a separate issue to be filed).