[Kolla] Transition Yoga and Zed to EOL

Hello, As agreed during the latest IRC meeting, Kolla Yoga and Zed deliverables (Kolla, Kolla-Ansible, Kayobe) are going EOL. [1] Antelope remains as unmaintained, while Bobcat, Caracal and Dalmatian are our current stable releases. Yoga and Zed branches were unmaintained for a while, Kolla community does not have resources to support those branches actively. All changes to those branches have been abandoned. [1] https://review.opendev.org/c/openstack/releases/+/937101 Best regards, *Jakub Darmach*