Add German Legal Notes to Resources

By using the “lang” attribute and an alias name, the German text will
automatically replace the English one on a system with German locale
without any need for modifications to the source code.

res/resources.qrc

@@ -7,6 +7,7 @@
   </qresource>
   <qresource prefix="legal">
     <file>legal-infos.htmlpart</file>
+    <file lang="de" alias="legal-infos.htmlpart">legal-infos.de.htmlpart</file>
     <file>gpl3.htmlpart</file>
     <file>lgpl3.htmlpart</file>
     <file>lgpl2.1.htmlpart</file>