Switch to UglifyJS that supports ES6 and up

[ggarek]

Issue:

What I did

Use uglify-es through uglifyjs-webpack-plugin to be able to minify es6+ code.

I stumbled upon same issue, then found this PR, which was not very active recently. So i submit this PR in continuation to original one.

How to test

I tested as proposed in the original PR. Here are some screenshots.

Build time (is ~28s)

Bundle size

1.8M	storybook-static/static/manager.84cf3a1cca5073d55149.bundle.js
1.2M	storybook-static/static/preview.09c4e2758e41ca532a7c.bundle.js

Note
I have no opportunity to check IE 😭

[Hypnosphi]

I changed base to release/3.3. Would you mind resolving the conflicts?

[ndelangen]

@ggarek Amazing you want to pick this up, thank you so much!

I would love to merge this as soon as possible.

I do think we need to adjust this not just for react and react-native, but also for Vue and Angular.
Would you be able to do that too? Please ask for help if you need it 👍

[ndelangen]

merged in master after the 3.3 merge (saved you the plain of the merge conflicts) and added the code to angular & vue

[codecov]

Codecov Report

Merging #2530 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #2530      +/-   ##
==========================================
- Coverage   32.69%   32.68%   -0.01%     
==========================================
  Files         398      398              
  Lines        8837     8838       +1     
  Branches      947      934      -13     
==========================================
  Hits         2889     2889              
- Misses       5298     5333      +35     
+ Partials      650      616      -34

Impacted Files	Coverage Δ
app/react/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
app/vue/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
...p/angular/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
...ct-native/src/server/config/webpack.config.prod.js	0% <0%> (ø)	⬆️
app/vue/src/server/config/babel.js	0% <0%> (-100%)	⬇️
...-native/src/preview/components/OnDeviceUI/index.js	0% <0%> (ø)	⬆️
addons/knobs/src/react/WrapStory.js	49.42% <0%> (ø)	⬆️
addons/info/src/components/Story.js	88.88% <0%> (ø)	⬆️
...react-native/src/manager/components/PreviewHelp.js	0% <0%> (ø)	⬆️
addons/jest/src/components/Result.js	0% <0%> (ø)	⬆️
... and 48 more

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[ndelangen]

CRA
Vue
Angular

[ndelangen]

Anyone from @storybooks/team want to review and possibly merge?