pod: Register pod against proxy
pod: Register pod against proxy

This is moved from createContainers/startShims to startProxy.
startProxy() is the first place where we can register the pod.

Signed-off-by: Samuel Ortiz <0ba86cb3f08bbb861958e54bd3438887adb4263c@linux.intel.com>

containers/virtcontainers,containers/virtcontainers