clean:

* updated method names to fit go conventions of uppercase. Db -> DB
* updated some method calls to use updated column select functions to remove extraneous empty string
* updated methods to use new label function that does nothing if no labels are passed in, this simplifies the code.
* updated some methods to use new Selectx function, reducing code in caller.

server/workflow_server.go

@@ -159,7 +159,7 @@ func (s *WorkflowServer) GetWorkflowExecution(ctx context.Context, req *api.GetW
 		return nil, err
 	}
 
-	mappedLabels, err := client.GetDbLabelsMapped(v1.TypeWorkflowExecution, wf.ID)
+	mappedLabels, err := client.GetDBLabelsMapped(v1.TypeWorkflowExecution, wf.ID)
 	if err != nil {
 		return nil, err
 	}