[goal] Migrate telemetry-tempest-plugin jobs to focal

As per victoria cycle testing runtime and community goal[1]
we need to migrate upstream CI/CD to Ubuntu Focal(20.04).

Most of the Tempest jobs will be migrate automatically once devstack
base job start running on Focal(Depends-On).

Stable jobs testing stable branch needs to keep running on their supported
distro version which is bionic from stein till ussuri.

Depends-On: https://review.opendev.org/#/c/752294/

[1] https://governance.openstack.org/tc/goals/selected/victoria/migrate-ci-cd-jobs-to-ubuntu-fo$

Change-Id: I7e032bb8848dd662432f846c51989180aa7c9b28
Story: #2007865
Task: #40223
1 file changed