Split up package.jsons for docs and lib again

[sambev]

Bringing them into one package is convenient for, well having just one, but I wonder if that cost is worth it.

So far there are two issues I think one is causing that I don't know how to fix otherwise:

1. CI bundle size checking (docs bundle vs lib bundle)
2. Minifying the lib build.

Webpack already minify's the doc build, but babel isn't minifying the lib. It probably should for production. Can webpack do both separately?

cc @jmophoto @cerinman @phantomxc

[cerinman]

We can define separate entry and output points in the webpack config file but having one package.json file can have unintended side effects when adding dependencies if they are placed in the wrong location in the file. The single webpack config file would also be more complicated.

I know it is more work to keep two separate package.json files in sync but I feel that it is less problematic to separate the concerns and have two files and if we want to minify the lib build then we can handle that with a separate config file as well.

[jmophoto]

Being the one that merged the two, I am thinking it would be best to break them apart again. Seeing issues with the hot reload.