By overriding the variable `swift_backend_ssl: True` HTTPS will
be enabled, disabling HTTP support on the swift backend api.
The ansible-role-pki is used to generate the required TLS
certificates if this functionality is enabled.
Depends-On: https://review.opendev.org/c/openstack/openstack-ansible/+/879085
Change-Id: Idb7882775a90ada9bb9e1450168916c73bf8ae4b