Add Discourse at https://community.ultralytics.com (#14231)

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: UltralyticsAssistant <web@ultralytics.com>

mkdocs.yml

@@ -173,6 +173,8 @@ nav:
           - 🇫🇷&nbsp Français: https://docs.ultralytics.com/fr/
           - 🇪🇸&nbsp Español: https://docs.ultralytics.com/es/
           - 🇵🇹&nbsp Português: https://docs.ultralytics.com/pt/
+          - 🇮🇹&nbsp Italiano: https://docs.ultralytics.com/it/
+          - 🇳🇱&nbsp Nederlands: https://docs.ultralytics.com/nl/
           - 🇹🇷&nbsp Türkçe: https://docs.ultralytics.com/tr/
           - 🇻🇳&nbsp Tiếng Việt: https://docs.ultralytics.com/vi/
           - 🇮🇳&nbsp हिन्दी: https://docs.ultralytics.com/hi/