title: How to clear existing models, or is there a way to re-Init monaco editor
body: <p>I'm using ngx-monaco-editor to implement a code editor in a modal.
  Because I need to support multiple tabs, I need to prepare a map for models to remember the models with Uris.
  The modal can also be reopened after closing it.</p>
  
  <p>Question:
  Once I reopen the modal and choose a file previously opened, it will throw error:</p>
  
  <pre><code>Cannot add model because it already exists
  </code></pre>
  
  <p>I'm not sure why ngx-monaco-editor does not destroy the models after the component is destroyed.</p>
  
  <p>Is there a way that I can manually clear those models before closing the modal.</p>