The SETTINGS->ExtCleanupDisk and SETTINGS->UnpackIgnoreExt options should do what you're looking for.

Oh, wait, that's not quite what you're looking for, I apologize.
As you mentioned, there are third-party plugins that can achieve this. They’re not included in the Docker image by default, you can manually install them by using docker exec to access the container and placing the extensions in your ${ScriptDir}.
Alternatively, you can wait until I add support for these extensions to the extension manager for easy installation.