Bug 24153: Add a confirm flag to cleanup_database

Bug 24153: Add a confirm flag to cleanup_database

How handy this will be, right?

This patch will change the behavior of this script as the --confirm flag
will now be required for effective changes.
Without --confirm and with --verbose you will see what could have done
the script in non dry-run mode.

Test plan:
Use different options of the script without the --confirm flag and have
a look at the output. It now tells you what would have been deleted if
the flag was passed.
Now use the --confirm flag and confirm that the changes are now
effective.

Sponsored-by: Association KohaLa - https://koha-fr.org/
Signed-off-by: Signed-off-by: Sonia Bouis <sonia.bouis@univ-lyon3.fr>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>