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 
Including `RequestBroadcast=true1` resolved the issue too.

```
    - name: dhcp.network
      content: |
        [Match]
        Name=ens*

        [Network]
        RequestBroadcast=true
```