MAINT: refactor webpack.config.js

[12rambau]

I updated the file to make it more readable:

• add comments and change variable names to make it more self-explanatory
• use one-liner when possible to pack functions and variables in blocs
• drop prettifying as all our strings are too long to be parsed
• extract the plugin init from module.exports to make it more readable
• get rid of unused libs (clean-webpack-plugin)

Fix #1030

[drammock]

LGTM, just a couple comments. I don't really understand how webpack works so I'm taking it on faith that you know what you're doing / the test will catch mistakes here.

[choldgraf]

This seems pretty good to me in general - the preview docs seem pretty good to me, let's merge it in after addressing @drammock's comments and iterate from there?

[12rambau]

let's merge it in after addressing @drammock's comments

Done

I don't really understand how webpack works so I'm taking it on faith that you know what you're doing / the test will catch mistakes here.

I'm no expert in webpack either but I'm positive that if something goes wrong (meaning the build of either css or js file fails) then the docs would not render properly in the pre-build. So I think we are on the safe side as everything went ok.