Documenting kinit_lifetime in /etc/ipa/default.conf
Describing the parameter kinit_lifetime that allows to limit the lifetime of ticket obtained by users authenticating to the WebGUI using login/password. Removing session_auth_duration and session_duration_type since these parameters are not relevant anymore.
Resolves: https://pagure.io/freeipa/issue/7333
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>