PostprocessData update

Modifications on fieldsDataBase to work both during simulation and post-simulation
Some bug fixes and changes to the code based
Correction for region volume

src/PostprocessData/operation/PostprocessOperation/PostprocessOperationSum.hpp

@@ -175,7 +175,9 @@ public:
     /// @brief Execute sum operation on field values
     /// @param weights Weight factors for particles
     /// @return True if successful
-    bool execute(const std::vector<span<real>>& weights) override;
+    bool execute(
+        const std::vector<span<real>>& weights,
+        const regionField<real>& volFactor) override;
 
 };