title: How to set the { observe: 'response' } option globally in Angular 4.3+?
body: <p>The first thought was to use an <code>HttpInterceptor</code> but the signature of the <code>clone(...)</code> method does not contain the <code>observe</code> option. Other than defining the <code>{ observe: 'response' }</code> option for each request, I don't see an alternative <em>yet</em> ... </p>
  
  <p>So, is there, if any, method to set the <code>{ observe: 'response' }</code> option <strong>globally</strong>, e.g. via the <code>HttpInterceptor</code>?</p>
  
  <pre><code>clone(update: {
     headers?: HttpHeaders;
     reportProgress?: boolean;
     params?: HttpParams;
     responseType?: 'arraybuffer' | 'blob' | 'json' | 'text';
     withCredentials?: boolean;
     body?: T | null;
     method?: string;
     url?: string;
     setHeaders?: {
         [name: string]: string | string[];
     };
     setParams?: {
         [param: string]: string;
     };
  }): HttpRequest&lt;T&gt;;
  </code></pre>