Add a method to IStatsCollector for returning stats as an OSDMap.

Extend implementors of IStatsCollector to return an OSDMap of stats.
Update UserStatsCollector and AssetStatsCollector to return both
string and OSDMap data (as well as console format).

OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs

@@ -12138,6 +12138,11 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             return String.Empty;
         }
 
+        public OSDMap OReport(string uptime, string version)
+        {
+            return new OSDMap();
+        }
+
         /// <summary>
         /// Make an asset request to the asset service in response to a client request.
         /// </summary>