Add number of scenarios running to help test

[sweeney-l]

This is a nice to have. But it might be useful once you run bacon if you were told how many scenarios will be run alongside the "Checking input files" "Loading input files" etc. just to give an idea of how long a run might take (so you can stop the run if you can see that there would be thousands of scenarios for example), maybe also with a max and min acc / thickness level. I know you can check this with a dry run, but just a suggestion.