Bug 37323: Don't allow symlinks in link files in zip and validate filepaths

Bug 37323: Don't allow symlinks in link files in zip and validate filepaths

Test plan:
0. Apply patch and restart/reload Koha
1. Test that uploading a patron image still works, in single file format and as a zip

Work as suggested

Signed-off-by: Amit Gupta <amit.gupta@informaticsglobal.com>
Signed-off-by: David Cook <dcook@prosentient.com.au>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>