Accommodate stable branches with scoped tokens

This patch updates the Designate tempest plugin to accommodate stable
branches that still have keystone scoped tokens. The "Direction
change"[1] means scoped tokens were dropped in the Bobcat (2023.2)
release. However the stable branches back to Wallaby will still have
scoped tokens available as a configuration option.

[1] https://governance.openstack.org/tc/goals/selected/consistent-and-secure-rbac.html#direction-change

Change-Id: Ia57b5126dbc9fbe98cbcaa7ad0e11d36c21a14da
11 files changed