Move README.md to root of bundled package & add keywords so that they shows on npmjs.org

[TomStrepsil]

The scout rule on #21:

Add README.mds to NPM packages, so npmjs.com doesn't appear empty

...attempted to provide a useful readme on homepages such as https://www.npmjs.com/package/@asos/web-toggle-point-webpack

However, it missed a pertinent point from npmjs.org docs:

An npm package README.md file must be in the root-level directory of the package.

To rectify, the README.md should be moved out of docs/ in the output package.

Could also consider adding keywords to package.json - they are currently set on the repo root, but that's no good for NPM.