Refactor to redux-toolkit

[asherccohen]

This is a great repo and article, very well explained.
We need more of these examples around.
One thing I suggest is to modernize the redux implementation with the new redux-toolkit and rtk-query.

It would make for a more interesting and up-to-date read.

Happy to review if you're willing to take the idea onboard.

[daslaf]

Hey @asherccohen

Yes of course, what I was initially planning was having different implementations of CounterStore using different libraries. If you want to contribute, feel free to submit a PR. 😄