Review fixes for 'Created metric class'

- Changed metric to_json to dumpConfiguration returning LabeledTuple
- LabeledTuple can be created and assigned directly to json
- LabeledTuple can be readed from json using json.get<LabeledTuple>
- Added PrintTo for LabeledMetricParams, LabeledSensorParams
- Added helper method expectMake to ReportFactoryMock
- sensorPaths are serialized to tuple<service, path> instead of single
  field with service and path separated via ':'
- Changed configuration version from 1 to 2

Change-Id: I7c45fb584687172f88fd549a93329264793b0b8e
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
diff --git a/src/interfaces/metric.hpp b/src/interfaces/metric.hpp
index d63c979..5a960a4 100644
--- a/src/interfaces/metric.hpp
+++ b/src/interfaces/metric.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "interfaces/types.hpp"
 #include "metric_value.hpp"
 
 #include <nlohmann/json.hpp>
@@ -16,7 +17,7 @@
 
     virtual void initialize() = 0;
     virtual const std::vector<MetricValue>& getReadings() const = 0;
-    virtual nlohmann::json to_json() const = 0;
+    virtual LabeledMetricParameters dumpConfiguration() const = 0;
 };
 
 } // namespace interfaces