Add auth rpc service to generate access keys, add corresponding test

pkg/server/router.go

@@ -117,6 +117,7 @@ func getRPCHandler() http.Handler {
 	s.RegisterService(new(rpc.MemStatsService), "MemStats")
 	s.RegisterService(new(rpc.DiskInfoService), "DiskInfo")
 	s.RegisterService(new(rpc.DonutService), "Donut")
+	s.RegisterService(new(rpc.AuthService), "Auth")
 	// Add new RPC services here
 	return registerRPC(router.NewRouter(), s)
 }