libvirt: enhance driver to configure guests based on hugepages

Work-Item: Enhance libvirt driver to configure guests based on
           the flavour parameter for page sizes

Partial-Implement: blueprint virt-driver-large-pages
Change-Id: Id9d826e83f3ee5720486efb8cb0ff38c0dfcc990
Merge "libvirt: enhance driver to configure guests based on hugepages"