net/filter-mirror:Add filter-mirror

Filter-mirror is a netfilter plugin.
It gives qemu the ability to mirror
packets to a chardev.

usage:

-netdev tap,id=hn0
-chardev socket,id=mirror0,host=ip_primary,port=X,server,nowait
-filter-mirror,id=m0,netdev=hn0,queue=tx/rx/all,outdev=mirror0

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Yang Hongyang <hongyang.yang@easystack.cn>
Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

vl.c

@@ -2841,7 +2841,8 @@ static bool object_create_initial(const char *type)
      * they depend on netdevs already existing
      */
     if (g_str_equal(type, "filter-buffer") ||
-        g_str_equal(type, "filter-dump")) {
+        g_str_equal(type, "filter-dump") ||
+        g_str_equal(type, "filter-mirror")) {
         return false;
     }