Start with clean environment

[rikedyp]

From an internal note:

Currently the Jupyter environment is protected from the user's environment (environment variables or .dcfg etc.) by init.dws. In the future we might change to a script based launcher but need to make sure the Jupyter environment starts with all defaults, to ensure that notebooks are run in a default environment.

This issue is to verify if the above is true and, if so, consider addressing it