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 
Hm, so that's not the problem then. The only other line in the default config for vmware is `UseMTU=true`, does including that cause your issue?