Store the full address as a computed field

dovecot/conf/dovecot-sql.conf.ext

@@ -5,12 +5,10 @@ connect = /data/freeposte.db
 password_query = \
  SELECT password \
    FROM user \
-  WHERE user.domain_name = '%d' \
-    AND user.localpart = '%n'
+  WHERE user.address = '%u'
 
 # Mostly get the user quota
 user_query = \
  SELECT '*:bytes=' || user.quota_bytes AS quota_rule \
    FROM user \
-  WHERE user.domain_name = '%d' \
-    AND user.localpart = '%n'
+  WHERE user.address = '%u'