Bug 19999: use Modern::Perl in label scripts

Bug 19999: use Modern::Perl in label scripts

Test Plan:
- Check that it now says 'use Modern::Perl;' and not 'use strict; use
warnings;' in the following labels perl scripts:

label-create-csv.pl
label-create-pdf.pl
label-create-xml.pl
label-edit-batch.pl
label-edit-layout.pl
label-edit-profile.pl
label-edit-template.pl
label-home.pl
label-item-search.pl
label-print.pl
spinelabel-home.pl
spinelabel-print.pl

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>