Auto backup save

[brauliodiez]

It would be a good idea to save a backup of the file every X minutes on the local storage, just in case somebody makes a mistake (e.g. pressing on back button) they would get the file loaded automatically.

We will have to warn that this is not the latest version etc

And once we have a settings dialog we could add a check to disable this

Before starting on this, check with @deletidev and @brauliodiez we have already a solution for this implemented in MongoModeler