bug_10781: Remove C4::ILSDI::Utility

bug_10781: Remove C4::ILSDI::Utility

This patch removes C4::ILSDI::Utility on the basis
that one of its routines (BorrowerExists) was not used
and that the other routine can be (and is) moved to
C4/ILSDI/Services.pm.

Test:
This should be a noop. Regression testing required:
/cgi-bin/koha/ilsdi.pl functioanality, in particuler:
GetAvailability - ?service=Describe&verb=GetAvailability
AuthenticatePatron - ?service=Describe&verb=AuthenticatePatron

ILS-DI syspref must be turned on

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 7675ede590936b7f32c665c3d597a9f34122f8ae)
Signed-off-by: Fridolin SOMERS <fridolin.somers@biblibre.com>