quicker and cleaner diagram image generation.
Remove etl-graph and mapping-graph targets - redundant
Also, the obsolete "fields" is still in Imposm's code and both names are accepted,
but "fields" is not documented anywhere (PR submitted), and could be removed at any moment.
Our docs were not supporting it until this PR, so renaming it at the same time.
Several images have been updated due to a more inclusive mapping scan
Requires https://github.com/openmaptiles/openmaptiles-tools/pull/147 (merged)
* Add better support for 3d buildings
Change key from "levels" to "building:levels" as the "levels" key is non-standard and sees much less use than "building:levels"
* Fix typo in sql definition and missing render_min_height
* Add render_height and min_height to building.yaml
* Simplify the render, switch numeric to int.
Assume min_height cannot be negative. There are a few examples in overpass, but can't show below ground anyways in mapbox (https://github.com/mapbox/mapbox-gl-js/issues/3456). Also don't attempt to fix min_height>height
* Remove colour as it is not currently used
