Bug 8368: fix email lists from OPAC when using non-English templates

Bug 8368: fix email lists from OPAC when using non-English templates

This patch ports to list sending by email, the technique used in sending
cart, i.e. (1) format email in HTML, and (2) transform it into Text with
TT filter html2text.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Fixes a very annoying translation bug successfully.
Also passes all tests and QA script.

To test:
- Add a few records to a shelf, ideally use some with diacritics.
- Send shelf from English templates, verify email is ok
- Send shelf from translated templates (de-DE or similar) - verify
  email content is broken.
- Apply patches, update po files and reinstall the language.
- Send shelf from English templates again, verify there is no
  regression.
- Send shelf form translates templates - verify this email is now
  also working correctly.

Patch also changes the name of the file attachement from shelf.iso2709
to list.iso2709.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit bbcc715c9435fc82fd6179722332128e4e5c6ee5)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>