Login requirement for local operations like help

It would be useful to avoid checking for user credentials when only the --help flag is used. https://gitlab.ethz.ch/vermeul/ethz-iam-webservice/-/blob/master/ethz_iam_webservice/main.py#L98

In my opinion the credentials should only be used when the login happens. The call to login() seems also inconsistent - once with credentials once without.