Update to example apps to support React 17 testing (#4698)
* partial progress
* adding ability to switch between react 17 and 18 in the CRA apps
* adding nextjs react 17 test app
* test react 17 setup in original next example
* test react 17 setup in tailwind example
* fix nextjs config for 17
* fixing more typos
* pushing temp progress for tailwind and react 17 nextjs app
* removing console.log
* testing that circleci still builds the apps
* Revert "testing that circleci still builds the apps"
This reverts commit fde37cd62de934a43ed7b89bcd4fa1afeaf65285.