Bug 27049: Add /misc/cronjobs/writeoff_debts.pl

Bug 27049: Add /misc/cronjobs/writeoff_debts.pl

This patch adds a new misc/cronjobs/writeoff_debts.pl script to allow the bulk
waiver of debts from the system. The script accepts some filter parameters,
including the option to pass a line delimited file of accountline_ids, and will
apply a WRITEOFF account against them for the amount of the outstanding debt.

Examples:
./writeoff_debts.pl --added_before $(date -d '-18 month' --iso-8601) --confirm
./writeoff_debts.pl --type COPY --verbose --confirm
./writeoff_debts.pl --file path/to/file --verbose

Test plan
1/ Add some debts to the system for various users.
2/ Output a line delimited report for accountlines for those debts.
3/ Run the script with the --file parameter and confirm those debts were
written off.
4/ Repeat steps 1-3 above but add in a step to partially pay some debts
prior to running the script.
5/ Repeat steps 1-3 above but pay of some of the debts prior to running
the script.
6/ Repeat steps 1-2 above, but instead of passing --file use a
combination of the other parameters to limit your list of debts to
writeoff.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>