Containerized nova-compute working with Deployed Server

Containerized nova-compute working with Deployed Server

When using the Deployed Server feature, we rely on Puppet to install
packages. But nova-compute/libvirt puppet is running in a container, so
it cannot install anything on the host. We rely on virtlogd on the host,
so we need to install it there some way. This patch uses host_prep_tasks
for that, conditionally based on the EnablePackageInstall stack
parameter value.

Also multinode-container-upgrade.yaml env is copied as
multinode-containers.yaml, to remove the naming confusion, as the
environment file can be used for more than just upgrades. The old env
file will be removed once we make the upgrade job use the new one (catch
22 type of issue).

Change-Id: Ia9b3071daa15bc30792110e5f34cd859cc205fb8