title: How to fix the add QLPreviewController as subview
body: <p>When loading the <code>PDF</code> in a <code>QLPreviewController</code>, it does not fit the content that I have inside, I am adding it as a subview to a container view. The <code>PDF</code> has a greater zoom than required. Is there any way to modify the zoom of <code>QLPreview</code>?</p>
  
  <pre><code>let preview = QLPreviewController()
      preview.dataSource = self
      preview.navigationController?.isNavigationBarHidden = true
      addChild(preview)
      termsConditionsContainer.addSubview(preview.view)
      termsConditionsContainer.backgroundColor = .white
      preview.view.translatesAutoresizingMaskIntoConstraints = false
      preview.view.topAnchor.constraint(equalTo: termsConditionsContainer.topAnchor).isActive = true
      preview.view.leftAnchor.constraint(equalTo: self.termsConditionsContainer.leftAnchor).isActive = true
      preview.view.widthAnchor.constraint(equalTo: self.termsConditionsContainer.widthAnchor).isActive = true
      preview.view.bottomAnchor.constraint(equalTo: termsConditionsContainer.bottomAnchor).isActive = true
      preview.didMove(toParent: self)
  </code></pre>