virt: introduce types VirtPageSize and VirtPagesTopology

Introduces a new types VirtPageSize and VirtPagesTopology

Work-item: Enhance libvirt driver to report available
           large pages per NUMA node in the host state data

Change-Id: I4a52bd204930245bd0539210a7f703efdeb06542
Partial-Implement: blueprint virt-driver-large-pages
Merge "virt: introduce types VirtPageSize and VirtPagesTopology"