Bug 29494: html-template-to-template-toolkit.pl no longer required

Bug 29494: html-template-to-template-toolkit.pl no longer required

This helper script was used to transition from HTML::Template to
Template::Toolkit, which happened 11 (?) years ago.

The file is part of Koha history, but we don't need it in current
master.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Owen <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>