add Néerlandais language option and make language_autre conditionally required

app/storage/schema.sql

@@ -90,7 +90,8 @@ CREATE TABLE IF NOT EXISTS languages (
 
 INSERT OR IGNORE INTO languages (name) VALUES
     ('Français'),
-    ('Anglais');
+    ('Anglais'),
+    ('Néerlandais');
 
 -- Format types (can select multiple)
 CREATE TABLE IF NOT EXISTS format_types (