build: current webpack config does not mimic the same functionality for global styles from Angular CLI

[christophercr]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[X] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/NationalBankBelgium/stark/blob/master/CONTRIBUTING.md#got-a-question-or-problem

Current behavior

In an app generated using the Angular CLI project, the files containing global styles should be included in the angular.json file at projects -> your-app -> architect -> build -> options -> styles.

This way, when using the ng serve command, Webpack will build the app including a styles bundle and add it to the index.html so global styles work as expected.

This is not the case when using the stark-build package instead of Angular CLI. Right now the global styles should be directly imported in the app.module.ts otherwise Webpack will not include them in the build and it will not create the styles bundle for them.

Expected behavior

The stark-build should mimic the same functionality for global styles as Angular CLI.

Minimal reproduction of the problem with instructions

1. Add a file with global styles under src/styles
2. Add the location of the file with global styles to the angular.json of the app under projects -> your-app -> architect -> build -> options -> styles
3. Make sure that you don't import the file with global styles anywhere in your app.
4. Start the application running the npm start command.
5. The global styles are not applied to the app because they are not even bundled by webpack

What is the motivation / use case for changing the behavior?

Make stark-build fully compatible (or as much as possible) with Angular CLI by respecting the API in the angular.json file.

Environment

Stark version: 10.0.0-beta.2