Directly export notebook app into interactive HTML

[YongcaiHuang]

Is your feature request related to a problem? Please describe.

I have many situation where I need to export the notebook app into HTML rendered by panel for sharing purpose. I understand there is .save method to export into HTML, but It needs me to explicitly concate and arrange the panel object before exporting. It is somehow not handy. Although jupyter nbconvert can export into HTML, but it is not interactive, not like panel

Describe the solution you'd like

It would be great if we can have some command line to export whole notebook into HTML in defaut layout or .servable() layout. e.g.:

panel export notebook.ipynb --servable

Describe alternatives you've considered

I have to explicitly concate and arrange the panel object before exporting