Switch to Fernet token format
Switch to Fernet token format

Configure Keystone's token driver for Fernet[0] instead of UUID.  The
latter has been deprecated for some time now, and will be removed as of
the 'Rocky' release of OpenStack[1].  Fernet has been the default since
'Ocata'.

NB:  This change is prompted by a bug in Keystone affecting federated
users and their group mapping[2].

[0] https://docs.openstack.org/keystone/queens/admin/identity-fernet-token-faq.html
[1] https://review.openstack.org/#/c/543060/
[2] https://bugs.launchpad.net/keystone/+bug/1758460

SKA-ScienceDataProcessor/alaska-kayobe-config