Dominik Locher airs Switzerland’s dirty laundry in Berlinale premiere “ Enjoy Your Stay ” by focusing on its undocumented workers.  “These are the people who work in the shadows and still contribute to this country’s wealth,” he states. Locher is also behind “Goliath.” “Switzerland has this postcard image. You think of the Red Cross, the League of Nations [known as the predecessor of the United Nations]. We wanted to flip this postcard over and take a look at the other side.” With the help of