Bug 24884: Remove 'New list' button in 'Public lists' tab if OpacAllowPublicListCreat...

Bug 24884: Remove 'New list' button in 'Public lists' tab if OpacAllowPublicListCreation is disabled

This patch adds a check on the OpacAllowPublicListCreation system
preference to the OPAC lists template so that if public list creation is
disabled the "New list" button doesn't appear under the "Public lists"
tab.

To test, apply the patch and confirm that the virtualshelves preference
is enabled.

- With the OpacAllowPublicListCreation system preference enabled, go to
  the OPAC and view the lists page.
  - If you are logged in you should see a "New list" link under both the
    "Your lists" tab and the "Public lists" tab.
  - If you are not logged in you should see "Log in to create a new
    list" on both pages.
- View the page with OpacAllowPublicListCreation disabled.
  - If you are logged in you should see a "New list" link under only the
    "Your lists" tab.
  - If you are not logged in you should see the "Log in" link only under
    the "Your lists" tab.

Works perfectly!

Signed-off-by: Caroline Cyr La Rose <caroline.cyr-la-rose@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>