this enables lxc to perform "disk-less migrations" where memory pages are sent directly to the destination machine instead of being written to the sources filesystem first.
For this, the migrate_opts struct has been added the strings "pageserver_address" and "pageserver_port" so that criu can be told where to look for a pageserver.
Signed-off-by: Niklas Eiling <niklas.eiling@rwth-aachen.de>