Replace map of the Baltic Sea

[axelboc]

Reported in a comment on the shared deck's page:

Being from Denmark I couldn't help but noticed how horribly disfigured Denmark is on the map of the Baltic Sea. It turns out that the picture is actually of the now gone 'Ancylus Lake' and therefore over 10.000 years old. https://en.wikipedia.org/wiki/Baltic_Sea#/media/File:Baltic_History_7500-BC.svg

Here's a better picture of the Baltic Sea with no name, maybe it's useful: http://www.nordregio.se/Global/Maps/Maps%20as%20pictures/Geographical%20scope/0731_Baltic%20Sea%20Region.png

The source and license of the suggested replacement map is unknown. Also, the map would require modification before being added to the deck.

In issue #1, I mention a Wikipedia category called Locator maps of seas. Although marked for improvement, the category does provide a reasonable locator map of the Baltic Sea, which could do for now: https://commons.wikimedia.org/wiki/Category:Locator_maps_of_seas#/media/File:Locatie_Oostzee.PNG