Bug 11944: Remove all utf8 filter from templates

Bug 11944: Remove all utf8 filter from templates

This patch
- removes all html_entity usages in tt file which hide utf8 bugs
- removes all encode utf8 in tt plugins because we should get correctly
  marked data from DBIC and other sources directly (cf plugin EncodeUTF8
  used in renew.tt)
- adds some cleanup in C4::Templates::output: we now use perl utf8 file
  handler output so we don't need to decode tt variables manually.

Signed-off-by: Paola Rossi <paola.rossi@cineca.it>
Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Dobrica Pavlinusic <dpavlin@rot13.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>