[de] new language variant "Simple German", with rules contributed by Annika Nietzio. In its own module, and not yet in stand-alone GUI because it needs some explanation for the user.

git-svn-id: https://languagetool.svn.sourceforge.net/svnroot/languagetool/trunk/languagetool@9623 2fe6a88b-1217-0410-b804-ba6ed01314b8