add namespace selector and pod selector functionality to network policy
add namespace selector and pod selector functionality to network policy

This code does some basic reorganization to pkg/ovn/policy_old.go
and adds the functionality to more closely support upstream kubernetes
network policy

Signed-off-by: Jacob Tanenbaum <1ca068bafd595100d13e841dfbdf857eefa7ddd2@redhat.com>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes