title: quasar can't build asset folder
body: <p>My project has <code>static</code> folder and <code>asset</code> folder. 
  I use  <code>quasar dev</code> to build project and the building project is stored in <code>dist</code> folder. But in the <code>dist</code> folder, it only has <code>static</code> folder, it doesn't has <code>asset</code> folder.
  How can I let <code>asset</code> be packaged in <code>dist</code> folder?</p>