Adds flag for enabling the creation of a disk partition

Change-Id: Id667208d1516031c770de830580afdf0176791de
Merge "Adds flag for enabling the creation of a disk partition"
Create the lib/vz/root/<ctid> directory if not exists

OpenVZ requires an empty folder in /lib/vz/root/<ctid> in order to
start a container. This folder is no longer being created by the
migration logic. This check creates it if it doesn't exist.

Change-Id: I21a5141d3b0b412922c1f112b7f505380c856efe
Container flavor settings and Vswap

* This allows for defining exact vz configs for specific flavor, instead
  of the driver calculating them.

* Vswap has been added as the new default way of setting memory settings

* Refactoring has been done to use new Container class.

Change-Id: I125682bbe89cedec08f328394ebb402a5c079b6d