[tripleo] Removing tempest container from TripleO

Hello, In TripleO CI jobs, we used to run tempest tests using a tempest container via tripleo-quickstart-extras 's validate-tempest role. Nowadays, All the tempest execution is done via openstack-ansible-os_tempest role in TrIpleO CI job which is dependent on tempest rpms. Validate-tempest is also getting removed. Since the tempest container is no longer used and tested in CI. So we are removing it from TripleO. Here is the tripleo-common patch for Removing tempest container build: https://review.opendev.org/c/openstack/tripleo-common/+/771993 Thanks for reading. Thanks, Chandan Kumar