Add banner on future of CRA to docs

Nick McCurdy
2023-03-19T08:57:27Z

### Is your proposal related to a problem?

There seems to still be confusion regarding the future of CRA (for example: https://github.com/facebook/create-react-app/issues/13072), as CRA's readme and docs don't mention the plans the core team has recently discussed on Twitter and GitHub. Additionally, many beginners are trying to find best practices on search engines, and since "create a react app" looks very similar to "create react app", search engines are still listing these docs on the first page of results (some still have it as the first result).

### Describe the solution you'd like

I'd suggest a simple banner in the docs, similar to the previous BLM and current Ukraine banners, making it clear that CRA is not currently recommended and linking to Dan Abramov's comment: https://github.com/reactjs/react.dev/pull/5487#issuecomment-1409720741

For example:

> Create React App is no longer recommended for new apps. [React Installation docs](https://react.dev/learn/installation) [Future of Create React App](https://github.com/reactjs/react.dev/pull/5487#issuecomment-1409720741)

### Describe alternatives you've considered

This may not be seen by all users, especially if they're using an older third party resource. If the `create-react-app` or `react-scripts` packages are not going to be used in the [future of CRA](https://github.com/reactjs/react.dev/pull/5487#issuecomment-1409720741), I'd recommend deprecating them. Otherwise, it would probably be a good idea to add a similar message to the logs of the CLI

Additionally, it may help to add migration guides. [Vite](https://vitejs.dev/) is the most straightforward replacement for CRA currently. If a similar tooling setup to CRA is desired, I also have an open source [Vite + React + Testing template](https://github.com/nickmccurdy/vite-react-testing).

### Additional context

Recently on Twitter Dan Abramov confirmed that the GitHub comment I linked is going to be the future of CRA. I could not find this, but if you do I can add it to my post.