Migrate ansible-hardening to zuulv3
Migrate ansible-hardening to zuulv3

This patch removes the ansible-hardening project definction so that
test jobs can move into the repo's .zuul.yml file.

Needed-By: I8022c2ce6620ccf1534832636f42efc909125585
Change-Id: I691ec60a2642bf08be2317c057827ac4fd853cc1

openstack-infra/project-config,openstack-infra/project-config