title: how to use optional url parameters with NestjS
body: <p>I'm trying to replace our current backend service using Nestjs library, 
  however, I want to create a route with 2 optional parameters in the URL something like : </p>
  
  <p><code>/route/:param1/config/:OptionalParam3?/:OptionalParam3?</code> </p>
  
  <p>that means the route should catch : </p>
  
  <ol>
  <li><code>route/aa/config</code></li>
  <li><code>route/aa/config/bb</code></li>
  <li><code>route/aa/config/bb/cc</code></li>
  </ol>
  
  <p>how can I achieve that, I have tried to use <code>?</code> and <code>()</code> but it's not working well.</p>