Bug 8980 - Untranslatable strings in modborrowers.pl

This patch removes the declaration of interface labels
from the script and puts it in the template where the
labels can be translated. The labels have been modified
to match those used on the patron entry form.

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>