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

This reverts commit 2c34d5b6.

To analyze Webpack bundles, a "stats" JSON is required.

This PR allows that file to be created and saved to the `build`
directory, so that users can use it with Webpack-specific insight
tools like `webpack-bundle-analyzer` without ejecting their
application.

Updated the README to include details for how to do this.

* 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

* Offer to set browser defaults

* Catch error on no

* Add ending newlines

* Ensure we re-check to prevent defaults from leaking

* Reduce nesting

* Add defaults message

* More explicit

* Warn about browsers during build

* Better message

Add preflight check to guard against wrong versions of webpack/eslint/jest higher up the tree (#3771)

* Run real scripts in local development

* Add preflight check warning

* I know what I am doing

* Move preflight check into individual scripts

This ensures we don't try to filter NODE_PATH twice, accidentally removing the now-absolute path.

* Slightly tweak the wording

* Fix lint

* File headers BSD+Patents -> MIT

* BSD+Patents -> MIT

* Move the reduction of the messages to a single place in the place it is used.

* Fix variable name

* format UglifyJs error

* move formatBuildError to react-dev-utils

* fix readme

* use regex for plucking the path from stack

* make path human readable and fallback to show error if regex not matched

* rename to printBuildError and add link to the docs

* fix link indentation

* improve readibility + shorten link

* Fix incorrect check if CI variable is set to true

Originally build would fail on warnings with any value of CI environment variable. Now it will correctly check if it's true.

Discussed here: https://github.com/facebookincubator/create-react-app/issues/2453

* Check for "not false" instead of "not true"

After discussion we decided that this will be closer to current functionality and not break anything.

* Print file sizes with correct build folder path.

* Just use the print the basename.

* Show warnings for builds

* Move WebpackDevServer helpers into react-dev-utils

* support different env configs.

* fomrat code

* Hide doc

* Slightly rework the PR

* Remove .env in default template
* Use just one entry in the paths
* Unify env.js and loadEnv.js

* Oops, forgot these folks

* Makes end-to-end testing crash on unhandled rejections

* Comment fix

* Suggest `serve` for serving the `build` directory

* How to handle it with Node in prod (or other platforms)

* Pretty newline added

* Adjusted default port of static server

* Remove `open` command from output

* Removed constant assignment

* Better explanation for not using having to use a static server

* Cute newline added

* Style nits

* mv create-react-app/index.js -> create-react-app/creteReactApp.js

* update to modern code style

* var -> cosnt

* set trailing-coma to es5 for prettier

* Temp rename

* Rename to change the case

* extract generic build functions to react-dev-utils

* tweak package json files and move removeFileNameHash

* revert removeFileNameHash

* use paths.appBuild in printFileSizes

* use paths.appBuild in removeFileNameHash

* change curried functions to regular functions

* add fs-extra to react-dev-utils deps

* move getDifferenceLabel inside printFileSizes

* inline copyPublicFolder

* combine printFileSizes and removeFileNameHash to fileSizeReporter

* fix typo

* Tweak APIs and fix issues

* Fix heading

* Remove missing file

* Newline

* Newline

* Trailing space

* Update FileSizeReporter.js

* Update build.js

* Setting a dynamic port value for the pushstate-server URL text after a build is completed

* Fixing merge conflict

Use the configured appBuild value in paths.js instead of hard-coding it to 'build'.  This is helpful for the ejected case where the appBuild path is changed to another folder name.

* (feat): add webpack validation error logging

* Style nit

* Style tweak

* Style nit

* Add `PUBLIC_URL` env variable for advanced use (#937)
* Add support for `PUBLIC_URL` env variable
* Remove unnecessary duplications
* Simplify served path choice logic
* Honor PUBLIC_URL in development
* Add e2e tests

Enables serving static assets from specified host.

* Added functionality to crash the build during CI whenever linter warnings are encountered.

* Updated the docs with a description on how to use the build in CI

* Fixed small typo

* Fixed description of build error.

In the `create-react-app` command, try to install packages using Yarn.
If Yarn is not installed, use npm instead.

In `react-scripts`, detect if the project is using Yarn by checking if
a `yarn.lock` file exists. If the project is using Yarn, display all
the instructions with Yarn commands and use Yarn to install packages
in `init` and `eject` scripts.

* Exit on any errors passed in build stats

* Match console error output in start.js