title: path to background-image in css with specific base href in Angular 9
body: <p>The baseHref param in angular.json is /iofrog/ + there are 7 languages defined in i18n.locales, so the final baseHref in index.html is /iofrog/en for English build. </p>
  
  <p>in css file for app component I have: </p>
  
  <pre><code>background-image: url('~/assets/img/background.jpg'); 
  </code></pre>
  
  <p>This is translated by Angular 9 CLI to path /iofrog/assets/img/background.jpg, so /en/ is skipped! Is it a bug in Angular CLI? </p>
  
  <p>I also tried:</p>
  
  <pre><code>background-image: url('/assets/img/background.jpg');  // not showing the image
  background-image: url('./assets/img/background.jpg'); // compiler error
  background-image: url('assets/img/background.jpg');  // not showing the image
  </code></pre>
  
  <p>I also found --rebaseRootRelativeCssUrls=true|false option but it is depreciated. </p>
  
  <p>The workaround that is working is in TS:</p>
  
  <pre><code>this.backgroundImageURL = `url(${this.baseHref}assets/img/background.jpg)`;
  </code></pre>
  
  <p>And in HTML template: </p>
  
  <pre><code>[style.background-image]="backgroundImageURL ? backgroundImageURL : ''"
  </code></pre>
  
  <p>But this is not elegant and the image is loading after the html is rendered. </p>
  
  <p>What is the correct solution in Angular 9? </p>