Improve E2e test playbooks

Created by: matofeder

Issue summarizes some improvements that have been pointed out in the review of PR #534 and could be addressed

• kubectl installation could be replaced by role/job ensure-kubectl, then this role/job could be re-used by other pipelines
• openstack ansible collection could be used instead of direct call of OpenStack CLI e.g.: openstack keypair delete {{ prefix }}-keypair"
  • mentioned direct OpenStack CLI calls are used in a cleanup play - this could be improved as suggested here, i.e. replace cleanup play by fullclean/forceclean as they are considered stable
• jobs k8s-cluster-api-provider-e2e-quick and k8s-cluster-api-provider-e2e-conformance differ actually in only one variable, so avoid DRY and create an abstract job that could be used as a base for both mentioned