Bug 13757: (followup) Staff interface changes

Bug 13757: (followup) Staff interface changes

This patch adds proper extended attributes display and handling on the
patron modifications moderation page (members-update.pl).

It also adds changes checking to the opac-memberentry.pl page so it
only saves a modification request if there are changes (it only checked
regular fields and not the extended ones).

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>