Transition from microbundle-crl to something else

This project was setup with the [create-react-library](https://github.com/transitive-bullshit/create-react-library) cli, which uses a fork (unmaintaned since last year) of [microbundle](https://github.com/developit/microbundle).

There are already [succesful transition to microbundle](https://github.com/transitive-bullshit/create-react-library/issues/284) (which is still developed/mantained) and probably this project should follow up on that as well. That should bring new features and better support in the long term.