Use scss-bundle for bundling scss files

[mofogasy]

Current behavior

In the SCION Workbench version 0.0.0-beta.26 we forgot to include a style sheet, which leads to applications not starting / building anymore. The following error is logged:

> [email protected] start C:\devsbb\scion-workbench-demo
> ng serve


Date: 2019-09-13T05:20:42.490Z
Hash: 020101783a168e1186ed
Time: 19538ms
chunk {main} main.js, main.js.map (main) 1.67 MB [initial] [rendered]
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 248 kB [initial] [rendered]
chunk {polyfills-es5} polyfills-es5.js, polyfills-es5.js.map (polyfills-es5) 380 kB [initial] [rendered]
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.08 kB [entry] [rendered]
chunk {styles} styles.js, styles.js.map (styles) 405 kB [initial] [rendered]
chunk {vendor} vendor.js, vendor.js.map (vendor) 7.41 MB [initial] [rendered]

ERROR in ./src/styles.scss (./node_modules/@angular-devkit/build-angular/src/angular-cli-files/plugins/raw-css-loader.js!./node_modules/postcss-loader/src??embedded!./node_modules/sass-loader/lib/loader.js??ref--13-3!./src/styles.scss)
Module build failed (from ./node_modules/sass-loader/lib/loader.js):

@import './lib/workbench.constants';

/**
 * Provides styles for view drag and drop.
 */
@mixin wb-view-tab-drag-image-theme($theme) {
  .wb-view-tab-drag-image {
    display: grid;
    position: fixed;
    overflow: hidden;
    user-select: none;
    box-sizing: border-box;
    color: $viewpart_tab-active-fgcolor;
    background-color: $viewpart_tab-active-bgcolor;
    pointer-events: none;
    box-shadow: 0 5px 5px -3px rgba(0, 0, 0, 0.2),
    0 8px 10px 1px rgba(0, 0, 0, 0.14),
    0 3px 14px 2px rgba(0, 0, 0, 0.12);
  }
}


       ^
      Can't find stylesheet to import.
  ╷
1 │ @import './lib/workbench.constants';
  │         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ╵
  node_modules\@scion\workbench\_view-drag-theme.scss 1:9  @import
  node_modules\@scion\workbench\_theming.scss 13:9         @import
  stdin 1:9                                                root stylesheet
      in C:\devsbb\scion-workbench-demo\node_modules\@scion\workbench\_view-drag-theme.scss (line 1, column 9)
** Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **
i ｢wdm｣: Failed to compile.

Expected behavior

In order to avoid such problems in the future, scss-bundle will be used for bundling all necessary style sheets when building the library.

Minimal reproduction of the problem with instructions

Update the SCION Workbench version of the Demo Application to version 0.0.0-beta.26 and then serve the application.

Environment

• SCION Workbench version: 0.0.0-beta.26
• Angular version: 8.0.0