Set `speedtest_enabled: true` in your `inventories/<your_inventory>/nas.yml` file.
If you want to access Speedtest-Tracker externally, don't forget to set `speedtest_available_externally: "true"` in your `inventories/<your_inventory>/nas.yml` file.
The Speedtest-Tracker interface can be found at http://ansible_nas_host_or_ip:8765.