Adjust the default browsers to be a single list and remove it from the build output; it only affects CSS now

Closes #4932, Closes #4876

* No lock files prevents the use of yarn upgrade & outdated

* Update deps

* Bump Jest across the board

* Add safe postcss parser

* Upgrade html webpack plugin

* Fix build

* fix FileSizeReporter in Windows enviroment

* chore: change line endings

This reverts commit 2c34d5b6.

This reverts commit 9690bc86.

Uglify is no longer maintained and has bugs not present in Terser (its successor)

* Update jest version

* Update babel-jest version

* Use testURL: http://localhost in jest configs.

* Update to jest version 23.5

This version of jest includes a fix for https://github.com/jsdom/jsdom/issues/2304

* "testURL": "http://localhost" is default with jest v23.5

* Use file name whitelist to prevent RCE

Use a whitelist to validate user-provided file names. This doesn't cover
the entire range of valid filenames but should cover almost all of them
in practice. Allows letters, numbers, periods, dashes, and underscores.
Opting to use a whitelist instead of a blacklist because getting this
wrong leaves us vulnerable to a RCE attack.

* Allow alphabet characters from all languages

Updated the whitelist to /^[\p{L}0-9/.\-_]+$/u, which matches
alphanumeric characters, periods, dashes, and underscores. Unicode
property support is stage 4 so I've inlined the transpiled version.

* Only use file name whitelist on Windows

* Log error message if file name does not pass whitelist

- [x] Utilize webpack 4 development and production modes
- [x] Upgrade webpack dev server
- [x] Webpack 4 compatible release of thread-loader
- [x] Webpack 4 compatible release of HtmlWebpackPlugin
- [x] Webpack 4 compatible release of SwPrecacheWebpackPlugin
- [x] Webpack 4 compatible release of WebpackManifestPlugin
- [x] Update README
- [x] Update WebpackDevServerUtils
- [x] Update InterpolateHtmlPlugin
- [x] Update ModuleScopePlugin
- [x] Update WatchMissingNodeModulesPlugin
- [x] Move UglifyJS options to webpack 4 optimize
- [x] Move InterpolateHtmlPlugin to make it tapable on HtmlWebpackPlugin
- [x] vendor splitting via splitChunks.splitChunks (https://twitter.com/wSokra/status/969633336732905474)
- [x] long term caching via splitChunks.runtimeChunk (https://twitter.com/wSokra/status/969679223278505985)
- [x] Make sure process.env.NODE_ENV is proxied correctly to `react-error-overlay`
- [x] Implicit webpack.NamedModulesPlugin in dev config as its default in webpack 4
- [x] Disable webpack performance hints as we have our own filesize reporter
- [x] Replace ExtractTextPlugin with MiniCssExtractPlugin
- [x] Switch to css whole file minification via OptimizeCSSAssetsPlugin rather than per module css minification to gain performance

* Update getCSSModuleLocalIdent to support Sass

* Fix Sass/SCSS index module tests

Also make them more consistent with the non-index variants.

* Updated jest version.

* Update CSS Modules localIndetName

* Add missing file to package

* Correct regex

* plz plz plz

* allow appSrc accepting an array

* fixture of finding all appSrcs logic

* update docs on ModuleScopePlugin accepts an array for appSrc

* minor typo fix in docs: change directory to directories.

* Add explicit dep on plugin-proposal-object-rest-spread to babel-preset-react-app

* Bump babel-related deps to beta.42

* Pass useBuiltIns directly to react-preset

Signed-off-by: petetnt <pete.a.nykanen@gmail.com>

* Run yarn after ejecting.

* On eject, choose to run yarn instead of npm if yarn is available.

* Move monorepo to react-dev-utils.

* Fix lint.

* Rename monorepo to workspaceUtils.

* Add react-dev-utils dep for create-react-app.

* getMonorepo -> findMonorepo

* change link to advanced deployment

* Use custom CRA link for deployment

* use custom link for minification failure

* update link for deployment

* feedback