Add LxcEngine

This engine make one deployment into lxc container, and then make
N clones of this container.
Also it can create tunnel to specified host. Tunnels is usable
when Openstack provider is used.

blueprint multihost-deploy

Change-Id: I61c9059d6721a0c94ca1ec5a8be14ad744c85d30
Merge "Add LxcEngine"