feat: add German address format

Close #1427

exampleSite/config/_default/params.toml

@@ -170,6 +170,7 @@ plugins_js  = []
 [address_formats]
   en-us = {order = ['street', 'city', 'region', 'postcode'], delimiters = [', ', ', ', ' ', '']}
   en-gb = {order = ['street', 'city', 'region', 'postcode'], delimiters = [', ', ', ', ', ', '']}
+  de = {order = ['street', 'postcode', 'city'], delimiters = [', ', ' ', '']}
   zh = {order = ['postcode', 'region', 'city', 'street'], delimiters = [' ', ' ', ' ', '']}
 
 # Configuration of publication pages.