Basemap improvements

[bchapuis]

Description: The basemap is in a good shape, but we can still improve it. This issue will be used to list and track these improvements. Please, do not hesitate to list further improvements that you may notice.

Guidelines: We build on the work done for osm-carto, but we do not copy every style rules. For instance, we avoid the use of patterns (e.g. trees in forest polygons), as they require a raster sprites and do not scale well. Additionnaly, we try to avoid dashed lines and other directives that affect rendering when zooming in or out.

How to help: You can pick and solve an issue or report new ones. For this, the dev mode of apache baremaps is really handful, as it allows to display the vector basemap and openstreetmap side by side. Additionaly, it allows to inspect the content of the tileset and to display the openstreetmap metadata.