Refactor Storybook off of Komposer/Mantra/Podda stack

[danielduan]

These packages have not been maintained for a while. As a stop gap measure, I've published the offending packages to silence some peer dependency warnings. #2303

[Hypnosphi]

Actually, we use redux in core/client for managing selected story, so we just need to move all the other state management there

[Hypnosphi]

Ok, I just realized that redux in core manages state in preview, and Kadira stack does it in manager. So it will be a separate store, but we can extract some shared helpers anyway

[danielduan]

I have second thoughts about even refactoring off this stack.

I spent a good few hours trying to understand how the state management and containers work within the @storybook/ui package. It doesn't seem like I can migrate things little by little, and it's a huge effort that'd be better spent just starting fresh with a new UI like the SBNext project.

[ndelangen]

WIP #4086

[shilman]

Released in alpha: https://github.com/storybooks/storybook/releases/tag/v5.0.0-alpha.0