This PR is to fix "[Examples] Problem with query parameters in with-redux-persist (#15484)"
The root cause is
persist/rehydrate action will issue twice when query parameter is set. But persistStore initial bootstrap is not ready yet. So i add a bootstrap callback and force persistor to persist again to make overall state correct. I also modify the loading prop to a `<div>loading</div>` because it's confuse to set Component in loading prop.
Attached the GIF
![demo](https://user-images.githubusercontent.com/1462027/89922530-bec04000-dc31-11ea-9831-12cd9d436d96.gif)
Closes#15484
* Moved the state to the clock component
* Refactored the store according to the new requirements
* Refactored _app so it uses the new store
* This file is no longer needed
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>