- add NotebookApp.login_token, used when NotebookApp.password is not set
- store login_token, bool(password) in notebook server-info file
- `jupyter notebook list` shows pasteable URLs with token
General changes:
- notebook servers are now authenticated by default
- first connect with token sets a cookie
- once a user has logged into one server with a token, their browser is logged in to
all subsequent servers on the same system+port until cookie_secret changes
There was a conflict for the .login_available property on LoginHandler itself
causing the login form to render incorrectly when login_available should be False