Create Item.System from Exposes List

Similar to how Item.BMC objects are created from
{
  "Name": "BMC",
  "Type": "BMC"
}

We should be able to create Item.System objects from the same config
{
  "Name": "host1",
  "Type": "System"
}

This will allow creation of Item.System objects from the Board config.

Performed following tests:
1. busctl tree shows object created by EM
2. busctl introspect also shows that it implements the Item.System
interface.

Tested: on QEMU

Change-Id: Ib9c22fa34ba7c8e00ab8f56ea58bee2bf32cdff9
Signed-off-by: Edward Lee <edwarddl@google.com>
diff --git a/src/entity_manager.cpp b/src/entity_manager.cpp
index 428d63e..ee08c00 100644
--- a/src/entity_manager.cpp
+++ b/src/entity_manager.cpp
@@ -697,6 +697,16 @@
                                           bmcIface, item, objServer,
                                           getPermission(itemType));
             }
+            else if (itemType == "System")
+            {
+                std::shared_ptr<sdbusplus::asio::dbus_interface> systemIface =
+                    createInterface(objServer, ifacePath,
+                                    "xyz.openbmc_project.Inventory.Item.System",
+                                    boardKeyOrig);
+                populateInterfaceFromJson(systemConfiguration, jsonPointerPath,
+                                          systemIface, item, objServer,
+                                          getPermission(itemType));
+            }
 
             populateInterfaceFromJson(systemConfiguration, jsonPointerPath,
                                       itemIface, item, objServer,