Bug 30042: Remove Date::Calc dependency in batch_anonymize.pl

Bug 30042: Remove Date::Calc dependency in batch_anonymize.pl

This patch makes the script use the Koha::DateUtils tools instead.

To test:
1. Run:
   $ kshell
  k$ perl misc/cronjobs/batch_anonymise.pl --verbose --days 7
=> SUCCESS: You see (the date may vary):
Checkouts and holds before 2022-02-15 will be anonymised.
2. Apply this patch
3. Repeat 1
=> SUCCESS: Same output
4. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>