Refine the rbacLogin behaviour
This is based on a discussion with @isinkare & RBAC expert @wsliwins (cc @mvoelkle).
The doc build for this branch can be found at https://acc-py.web.cern.ch/gitlab/pelson/pyjapc/docs/feature%2Fimproved_rbac_login_docs/api_docs/pyjapc.PyJapc.rbacLogin.html#pyjapc.PyJapc.rbacLogin