storybook, npm, webpack setup - draft

[pietrop]

Is your Pull Request request related to another issue in this repository ?

mostly based on #135 but also related to #130, #129

Describe what the PR does

Based on PR #135 provides a guide for setting up storybook with npm to publish components. Drafted for bbc/digital-paper-edit-storybook setup.

State whether the PR is ready for review or whether it needs extra work

Ready for review by @jamesdools @emettely
cc @allishultes

Additional context

NA

Just a draft, see if it makes sense, and feel free, to change/clarify. It be good to capture this setup if we are going to re-use in DPE etc..

[allishultes]

Looks good overall - I haven't tried to set it up but have left a few comments. There's some editing (spelling, grammar) I'd do too but this is ultimately clear.

[emettely]

If you are going to mention historical changes, you would need to describe it more - not much how and why, so when you mention babel I'm a bit puzzled as to why you mention it.