conf, schema: add support for numatune memnode element

This element specifies similar settings as the memory element,
although memnode can be used per guest NUMA node.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
conf: add virDomainGetMemsForGuestCpu()

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
qemu: purely a code movement

to ease the review of commits to follow.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
qemu: memory-ram capability probing

The numa patch series in qemu adds "memory-ram" object type by which
we can tell whether we can use such objects.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
qemu: pass numa node binding preferences to qemu

Currently, we only bind the whole QEMU domain to memory nodes
specified in nodemask altogether.  That, however, doesn't make much
sense when one wants to control from where the memory for particular
guest nodes should be allocated.  QEMU allows us to do that by
specifying 'host-nodes' parameter for the 'memory-ram' object, so
let's use that.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>