Initial check in of the D1NodeService class that provides methods common to both CNodeService and MNodeService implementation classes. The common API methods are:
Methods common to CNCore and MNCore APIs
Methods common to CNRead and MNRead APIs
Note: getChecksum() differs (the MN interface lists the checksum algorithm, CN doesn't), and this needs to be reconciled.
Methods common to CNAuthorization and MNAuthorization APIs
This class, along with CNodeService, will replace CNCoreImpl.