cubicweb-leaflet #4478567 Fit map markers if initial zoom is unset [done]

If settings.initialZoom is not specified, the default behaviour should be to choose the best zoom level that fits all map markers.

prioritynormal
typeenhancement
done in<not specified>
load0.250
load left0.000
closed by#ea06df425848 Guess the best zoom level if initialZoom is unset (closes #4478567)
patchGuess the best zoom level if initialZoom is unset (closes #4478567) [applied]