Map placeholder same size as map

[Tobi406]

The map placeholder should be the same size as the map to reduce big layout changes.
The placeholder should be on the server side and with a button to load the map. This should at best reduce the initial load.
Maybe the button choice could be saved in localStorage or as a cookie.

Current state:

• Button on map
• Button choice saved in localStorage or as a cookie

[Tobi406]

Done partly in 62295cc

Which reduced layout shift from 0.2 to 0 and gave +6 on performance