containers: added netns/netns_devices.sh and netns/netns_devices2.sh

* Tests that a separate network namespace can configure and communicate
  over the devices it sees
* netns/netns_devices.sh  -- uses netlink(7) for configuration
* netns/netns_devices2.sh -- uses ioctl(2) for configuration

Signed-off-by: Matus Marhefka <mmarhefk@redhat.com>