Kubeadmin cannot log into JupyterLab seemingly because of the `:` in its name. While kubeadmin itself will not be supported in RHODS, other users might have special characters in their usernames and face the same issue if JH is not able to escape these characters properly (e.g. `@`, `?`, etc.; `-`, which we currently use, is considered safe).

We need to create users in our test clusters with special characters in their names to make sure that the 403 Forbidden error does not appear for any of them.

cc vpavlin@redhat.com found the kubeadmin bug and suggested we run this test