Update contentdb_url to content.minetest.net

src/defaultsettings.cpp

@@ -284,7 +284,7 @@ void set_default_settings(Settings *settings)
 #endif
 	settings->setDefault("font_size", font_size_str);
 	settings->setDefault("mono_font_size", font_size_str);
-	settings->setDefault("contentdb_url", "https://contentdb.rubenwardy.com");
+	settings->setDefault("contentdb_url", "https://content.minetest.net");
 
 
 	// Server