Bug 18414: Allow to use other select criteria with delete_patrons.pl

Bug 18414: Allow to use other select criteria with delete_patrons.pl

Adds the ability to specify a file with the --file flag that
should be a list of borrowernumbers for deletion.
If used without other flags it will delete the list of borrowers,
if used with other flags it will treat the other criteria
as filters for the list.

To Test:
1) Specify a list, e.g. borrowers.txt, of borrowernumbers in the database and put them in a text file with one per line
2) Invoke the script like ./delete_patrons.pl --file borrowers.txt to delete those patrons
3) Populate the list with a mix of borrowers in a category and those not, say categoryfoo
4) Invoke the scirpt as ./delete_patrons.pl --category_code categoryfoo --file borrowers.txt
5) Only the borrowers in the file that have the specified category will be deleted

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>