nwbind: implement NCP 17/4c list object relations

Implement the Bindery "List Relations of an Object" endpoint.

Parse the NCP 17 subfunction 0x4c request, look up the requested bindery
object and set property, and return up to 32 related object IDs from the set
property value segments. Support the Novell last-seen cursor convention where
0xffffffff starts a new scan and subsequent calls continue after the last
returned object ID.

Add a small nwdbm helper for listing set-property members while preserving the
existing bindery property read-right checks. Reject wildcard object names with
the documented illegal-wildcard completion code.

include/nwdbm.h

@@ -206,6 +206,11 @@ extern int nw_delete_obj_from_set(int object_type,
 	        int   member_type,
 	        uint8 *member_name, int member_namlen);
 
+extern int nw_list_obj_relations(int object_type,
+	        uint8 *object_name, int object_namlen,
+	        uint8 *prop_name, int prop_namlen,
+	        uint32 last_seen,
+	        uint32 *relations, int max_relations);
 
 
 extern int nw_write_prop_value(int object_type,