Enable installing python packages on top of the selected image

[MarcSkovMadsen]

When trying to deploy a dashboard the available environments might contain the packages that the dashboard needs. Similarly drivers etc. might be missing.

Solution

Enable users to specify packages, apt-get packages etc. that should installed on top of the image.

Additional Context - Start script of Binder

When using Binder it is possible to setup a start script that runs additional commands before launching the app/ server. For example like this one https://github.com/holoviz/panel/blob/binder/binder/start