Add translations for various purposes in nodac

nodac/de/languser.json

@@ -17,6 +17,8 @@
         "admin": "Administrator",
         "groupadmin": "Gruppen-Administrator",
         "editor": "Bearbeiter",
-        "switch_language": "Sprache wechseln"
+        "switch_language": "Sprache wechseln",
+        "month": "month",
+        "year": "year"
     }
 }