The `upload` and `download` commands of Canvas CLI have been deprecated for a few months. Let's remove their implementation from the codebase. While doing this, we can also remove the `--no-tailwind` flag: We haven't really implemented this option in the `@drupal-canvas/discovery` package and the new build command, and there is no way to disable it in the in-browser code editor either, so it's best to not give the impression that the Tailwind CSS build can be skipped currently. Let's add back this option cleanly everywhere if/when the time is right.