Onboarding - ask user what variables they want to update

As of now, we are updating (or overwriting) all the QTCLOU_* variables in the project. However, a good method would be to ask the user if they want to update that variable? 

One thing to be noted, the conan credentials will always get overwritten because they are changed on every query and since they are the most important variables to add to CI, we might even skip this task.