This function adds a node registration to a directory service, or modifies
 a current node registration.

 When the node name is entered, it is checked to see if it already exists
 in the directory service.  If it does not yet exist, a message is
 displayed indicating that a new node is being registered.  This feature
 is used when a new node is made available in the network, and the node
 registration needs to be added to a directory service to allow lookup by
 other nodes.

 If the node name already exists, a message is displayed indicating that
 the node name is being modified, and the currently registered values are
 read and presented as inout defaults.