Adding custom banners to checkout

Previously, you created a checkout extension that renders some text in the checkout flow. Now you want to render the text as a banner.

In this tutorial, you'll use the Checkout::Dynamic::Render extension point and checkout UI components to build the banner. You'll use configuration fields, so that merchants can configure the banner's title, text, and status level. You'll also provide support for static extension points. Merchants can use the checkout editor to render the extension in one of the supported locations in checkout.

The custom banner in checkout, indicating that items are final sale and can't be returned or exchanged

TODO: A gif/visual of merchants setting the content for it within the checkout editor. It will start with an image or gif of what's being built, to orient Partners to what they can expect to end up with at the end of the tutorial.