Port init config files to Namecoin

The [init config files](https://github.com/namecoin/namecoin-core/tree/dev/contrib/init) in our repo still refer to Bitcoin.  We should port them to Namecoin.

This was originally reported in https://github.com/namecoin/namecoin.org/issues/78 .