hardware: determine whether a pagesize request is acceptable

Enhances numa_fit_isintance_cell to return whether the cell host
can handle the page size request

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: Ib8546c2a22017f738f644b94dcf00f4afd3582fc
Merge "hardware: determine whether a pagesize request is acceptable"