make nameserver information available on http server, add NameServerConfig

make nameserver information available on http server, add NameServerConfiguration
OK, I understand the need. But if we follow down this path, the `reef-webserver` package will have to have an enumeration of all possible REEF services. This tight coupling is worrisome when supporting 3rd party services. Can we instead turn this around and have `reef-webserver` expose an API that the various services implement? That way, all services depend on `reef-webserver`, but there is never a dependency the other way around.