Double mount issue

[Karnith]

Quasar mounts app in client-entry.js to q-app. Single-spa does not require this since we are using vue createApp method to mount the App.vue. Used webpack string-replace-loader to comment out the start(app, boot) function so that app is not mounted until single-spa mounts it which gets rid of the vue warning stating mount element #q-app returns null.