Add a correct native browser print

This PR adds a correct layout for the map when printing in A4 with the native browser function. 

The same code could be use to fix #1251 .

Test [here](http://mf-geoadmin3.dev.bgdi.ch/dev_printbrowser/prod/?lang=fr&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe&X=190000.00&Y=660000.00&zoom=1)

Compare without [whitespaces](https://github.com/geoadmin/mf-geoadmin3/pull/1325/files?w=1)