Bug 26256: Move translatable strings out of templates and into serials-toolbar.js

Bug 26256: Move translatable strings out of templates and into serials-toolbar.js

This patch removes the definition of translatable strings out of
templates and into the corresponding JavaScript file, using the new JS
i81n function.

To test:

- Apply the patch and go to Serials and search for a subscription.
- Open the detail page for an open subscription.
- Click the "Close" button. You should get a confirmation, "Are you
  sure you want to close this subscription?"
- Confirm that you want to close it.
- When the page reloads, click the "Reopen" button. You should get a
  confirmation, "Are you sure you want to reopen this subscription?"
- Cancel.
- Choose Edit -> Delete subscription. You should get a confirmation,
  "Are you sure you want to delete this subscription?"
- Perform the same tests from the "Serial collection" page.

TESTING TRANSLATABILITY

- Update a translation, e.g. fr-FR:

  > cd misc/translator
  > perl translate update fr-FR

- Open the corresponding .po file for JavaScript strings, e.g.
  misc/translator/po/fr-FR-messages-js.po
- Locate strings pulled from
  koha-tmpl/intranet-tmpl/prog/js/serials-toolbar.js for translation,
  e.g.:

  msgid "Are you sure you want to delete this subscription?"
  msgstr ""

- Edit the "msgstr" string however you want (it's just for testing).
- Install the updated translation:

  > perl translate install fr-FR

- Switch to your newly translated language in the staff client
  and repeat the test plan above. The translated strings should
  appear.

Signed-off-by: Alexis Ripetti <alexis.ripetti@inLibro.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>