Add Dutch language

Author: Jelcoo

frontend/src/locale/src/lang-list.json

@@ -25,8 +25,11 @@
 	},
 	"locale-it-IT": {
 		"defaultMessage": "Italiano"
-  },
+	},
 	"locale-vi-VN": {
 		"defaultMessage": "Tiếng Việt"
+	},
+	"locale-nl-NL": {
+		"defaultMessage": "Nederlands"
 	}
 }