First part of patchset:
 https://review.opendev.org/c/openstack/kolla-ansible/+/799229/


in which was suggested to split patch into smaller ones.

This implements kolla_container_engine variable
in command calls of docker,so later on it can be
also used for podman without further change.

Signed-off-by: Ivan Halomi <i.halomi@partner.samsung.com>
Change-Id: Ic30b67daa2e215524096ad1f4385c569e3d41b95