created AddReportFutureVersion dbus method

New method will support CollectionTimeScope, CollectionDuration

In order to make not breaking interface changes bmcweb will switch to
AddReportFutureVersion, then AddReport will be changed to match
AddReportFutureVersion, then redfish will switch back to use AddReport,
then AddReportFutureVersion will be removed.

Change-Id: I9cc906cc1fa7cdf27be7e433390c516f6bae3c50
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
diff --git a/src/utils/tstring.hpp b/src/utils/tstring.hpp
index a8d3e90..3e85ba5 100644
--- a/src/utils/tstring.hpp
+++ b/src/utils/tstring.hpp
@@ -56,5 +56,21 @@
     }
 };
 
+struct CollectionTimeScope
+{
+    static std::string str()
+    {
+        return "collectionTimeScope";
+    }
+};
+
+struct CollectionDuration
+{
+    static std::string str()
+    {
+        return "collectionDuration";
+    }
+};
+
 } // namespace tstring
 } // namespace utils