Print Scale Calculation

This PR adresses #938 

The scale calculation now takes the navbar at the top and the accordion to the left into account to calculate the next lowest scale that fits the visible area. This should avoid cases where the user does not see the actual print rectangle.

Note: we don't support bigger scales than 1:500, meaning that at high zoom levels, the rectangle will not be visible anymore

Note: if we activate Print on mobile, we maybe need to adapt again (because on mobile, we don't have navbar and accordion in the view)