NUMA: add qmp command set-mem-policy to set memory policy for NUMA node

This QMP command allows user set guest node's memory policy
through the QMP protocol. The qmp-shell command is like:
    set-mem-policy nodeid=0 policy=membind relative=true host-nodes=0-1

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
NUMA: add hmp command set-mem-policy

Add hmp command set-mem-policy to set host memory policy for a guest
NUMA node. Then we can also set node's memory policy using
the monitor command like:
    (qemu) set-mem-policy 0 policy=membind,relative=false,host-nodes=0-1

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
NUMA: add qmp command query-numa

Add qmp command query-numa to show guest NUMA information.

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
NUMA: convert hmp command info_numa to use qmp command query_numa

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>