in cocalc-docker, make it so classical Jupyter Notebook and also Jupyter Hub both require authentication

[William Stein]

First, we change the command line that is run when you click the "JupyterLab server" and "Classical Jupyter" server button in +New (and project settings), so it requires the use to authenticate somehow.

We will somehow have to then convey whatever the secret password is to the user, since I don't think it can be passed in the URL anymore.

Alternatively, we could make this functionality be completely disabled by default, and an admin user could optionally enable it (with a huge security warning).