add(coreos-base/oem-niftycloud): added initial oem for niftycloud

These are the initial oem scripts for niftycloud.
NIFTY Cloud is one of the most popular public cloud service in Japan.

cc: @kelseyhightower 
Restart of networkd didn't fix it.

```
Dec 12 04:22:24 localhost systemd[1]: Starting Network Service...
Dec 12 04:22:24 localhost systemd-networkd[5332]: ens224          : gained carrier
Dec 12 04:22:24 localhost systemd-networkd[5332]: ens192          : gained carrier
Dec 12 04:22:24 localhost systemd-networkd[5332]: lo              : gained carrier
Dec 12 04:22:24 localhost systemd[1]: Started Network Service.
Dec 12 04:22:24 localhost systemd-networkd[5332]: ens224          : link configured
Dec 12 04:22:24 localhost systemd-networkd[5332]: ens192          : link configured
Dec 12 04:22:24 localhost systemd-networkd[5332]: lo              : link configured
Dec 12 04:36:58 localhost systemd[1]: Stopping Network Service...
```

And here is a boot log:
https://gist.github.com/higebu/005a066524d5e0d34468