Keep the errors as we are seeing them and print or send a report at the end
    
    While the script runs, we're keeping in memory a list of all the errors
    we have encountered and at the end of the run we send to the admins a
    report with all of them, categorized in a way that will hopefully make
    it easier to fix for them.
    
    We're also adding an option to preserve the function to send the report
    to the admins but disable sending the notifications to the
    users/packagers.
    This would be useful to start get an idea of the number of people who
    would have issues with the script.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>