[Imagery] Add basemap.de as replacement for Maps4BW going to be turned off

[hhtznr]

When selecting Maps4BW (www.lbl-bw.de) as imagery source, each tile shows a message that the service will be turned off on 31.02.2023 and one should refer to basemap.de as alternative.

Hence, basemap.de should be added to the imagery default entries.

I was able to manually add the WMS Web Raster Farbe (web raster color) map from basemap.de with the "Add new WMS entry" wizard providing this capabilities URL: ​https://basemap.de/dienste/wms_capabilities_web_raster.xml

The wizard generated this URL for me and it works: wms:https://sgx.geodatenzentrum.de/wms_basemapde?FORMAT=image/png&TRANSPARENT=TRUE&VERSION=1.3.0&SERVICE=WMS&REQUEST=GetMap&LAYERS=de_basemapde_web_raster_farbe&STYLES=&CRS={proj}&WIDTH={width}&HEIGHT={height}&BBOX={bbox}

General instructions from basemap.de can be found here (in German):
​https://gdz.bkg.bund.de/index.php/default/webdienste/basemap-webdienste/wms-basemapde-webraster-wms-basemapde-webraster.html
​https://sgx.geodatenzentrum.de/web_public/gdz/dokumentation/deu/basemap.de_web_raster.pdf

[skyper]

Currently the license is incompatible with OSM. Please, do not use these new services. We have to wait and hope that we get a solution, see ​https://community.openstreetmap.org/t/maps4bw-und-basemap-de/6762.