Export codelist command

* adds a useful custom command which exports a specific selectable codelist into a csv file

codelist/management/commands/update_codelist.py

@@ -23,7 +23,7 @@ bool_map = {
 
 
 class Command(BaseKonovaCommand):
-    help = "Performs test on collisions using the identifier generation"
+    help = "Updates internal codelist by external API"
 
     def handle(self, *args, **options):
         try: