Add object manager

Added object manager to FanCtrl node so that it can be queried mapper
and GetManagedObjects method can be called.

Tested: verified this using busctl command and see object manager
interface has been added to this service.

Signed-off-by: Bruce Lee <Bruce_Lee@quantatw.com>
Change-Id: Ibbd6f63993aa26914fa42d0205263fd7a490f95e
diff --git a/main.cpp b/main.cpp
index 749bf77..342b27e 100644
--- a/main.cpp
+++ b/main.cpp
@@ -35,6 +35,7 @@
 #include <boost/asio/steady_timer.hpp>
 #include <sdbusplus/asio/connection.hpp>
 #include <sdbusplus/bus.hpp>
+#include <sdbusplus/server/manager.hpp>
 
 #include <chrono>
 #include <filesystem>
@@ -260,6 +261,7 @@
         static_cast<sdbusplus::bus::bus&>(modeControlBus), modeRoot);
     hostBus.request_name("xyz.openbmc_project.Hwmon.external");
     modeControlBus.request_name("xyz.openbmc_project.State.FanCtrl");
+    sdbusplus::server::manager::manager objManager(modeControlBus, modeRoot);
 
     /*
      * All sensors are managed by one manager, but each zone has a pointer to