Add activation, item_updater and version

Implement part of functions of Activation, ItemUpdater and Version.

Tested: Upload a dummy PSU tarball, and verify the activation object is
        created with expected ExtendedVersion, and the object is deleted
        when Delete is invoked.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: I7b9d29f46914ace93d27a715b32c80957e88a0aa
diff --git a/src/main.cpp b/src/main.cpp
index 905869d..fe9062e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,4 +1,27 @@
-int main()
+#include "config.h"
+
+#include "item_updater.hpp"
+
+#include <phosphor-logging/log.hpp>
+#include <sdbusplus/bus.hpp>
+#include <sdbusplus/server/manager.hpp>
+#include <system_error>
+
+int main(int /* argc */, char* /* argv */[])
 {
+    auto bus = sdbusplus::bus::new_default();
+
+    // Add sdbusplus ObjectManager.
+    sdbusplus::server::manager::manager objManager(bus, SOFTWARE_OBJPATH);
+
+    phosphor::software::updater::ItemUpdater updater(bus, SOFTWARE_OBJPATH);
+
+    bus.request_name(BUSNAME_UPDATER);
+
+    while (true)
+    {
+        bus.process_discard();
+        bus.wait();
+    }
     return 0;
 }