title: Using a remote entry with webpack
body: <p>I'm trying to set up a webpack config in a server enviroment that can output a bundle from a remote source. The source is a .js file and will be fetched through GET-requests. Is this possible?
  <br><br><br>
  <strong>Remote file - example.com/file.js</strong></p>
  
  <pre><code>export default () =&gt; console.log('Hello world');
  </code></pre>
  
  <p><br>
  <strong>Webpack with pseudocode</strong></p>
  
  <pre><code>const remoteSource = await fetchFromURL('http://example.com/file.js');
  
  webpack({
    entry: remoteSource,
    output: {
      filename: 'output.js',
      path: path.resolve(__dirname, 'src'),
      libraryTarget: "umd",
    }
  })
  </code></pre>
  
  <p>Any ideas are appreciated! </p>