🌐(i18n) activate dutch language

All the dutch translations are complete on crowdin. We activate it in
the django settings and download all translations from crowdin

Author: lunika

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to
 - ✨(frontend) add pinning on doc detail #711
 - 🚩(frontend) feature flag analytic on copy as html #649
 - ✨(frontend) Custom block divider with export #698
+- 🌐(i18n) activate dutch language #742
 
 ## Changed
 

src/backend/core/tests/test_api_config.py

@@ -43,6 +43,7 @@ def test_api_config(is_authenticated):
             ["en-us", "English"],
             ["fr-fr", "Français"],
             ["de-de", "Deutsch"],
+            ["nl-nl", "Nederlands"],
         ],
         "LANGUAGE_CODE": "en-us",
         "MEDIA_BASE_URL": "http://testserver/",

src/backend/impress/settings.py

@@ -238,6 +238,7 @@ class Base(Configuration):
             ("en-us", "English"),
             ("fr-fr", "Français"),
             ("de-de", "Deutsch"),
+            ("nl-nl", "Nederlands"),
         )
     )