Buildings from ways and multipolygons are loaded in table `osm_building_polygon`. But a table for `osm_building_multipolygon` is also loaded, the content is not used except to ensure an `osm_id` is from a multipolygon. To check if the object is from a multipolygon we have only to check if `osm_id` is negative. It is the counter part of e0c8ece375/layers/building/building.sql (L89)
I checked the objects are the same after this change.
Seems like etl and mapping diagrams have been neglected
for a long time. Now it regenerates the files and places
them in the source dir.
This PR also fixes two broken files:
* layers/aerodrome_label/mapping_diagram.png
* layers/housenumber/mapping_diagram.png
They were generated using the newest tools version with the fix
https://github.com/openmaptiles/openmaptiles-tools/pull/65
