Refactor::MergeNodes handle relationship properties

[damianbenente]

Currently the void Refactor::MergeNodes( work grate for the nodes but for the relationships it only recreate in a new one pointing to the merged node but the new one is empty discarding all the properties as the graph.CreateRelationship doesn't handle properties

...

// Handle relationships
      // Copy all relationships from source to target
      if (mergeRels) {
        auto in_rels = source_node.InRelationships();
        for (const auto &rel : in_rels) {
          graph.CreateRelationship(rel.From(), target_node, rel.Type());
        }

        auto out_rels = source_node.OutRelationships();
        for (const auto &rel : out_rels) {
          graph.CreateRelationship(target_node, rel.To(), rel.Type());
        }
      }

      // Delete the source node
      graph.DetachDeleteNode(source_node);
    }

it would be nice if it can handle to recreate the properties to maybe something like

if (mergeRels) 
        auto in_rels = source_node.InRelationships();
        for (const auto &rel : in_rels) {
          auto new_rel = graph.CreateRelationship(rel.From(), target_node, rel.Type());
          new_rel.SetProperties(rel.Properties);
        }


        auto out_rels = source_node.OutRelationships();
        for (const auto &rel : out_rels) {
          auto new_rel = graph.CreateRelationship(target_node, rel.To(), rel.Type());
          new_rel.SetProperties(rel.Properties());
        }
      }

• I don't have any experience with the c++ api so maybe the code is not wright or need modifications, if its there a easy way to make a dev environment to compile and test it I can do it, have experience with c++ but for embedded microcontrollers that the dev part are simpler. otherwise it looks like a simple change with will improve a lot the refactor module.