Bug 25211: Add missing share icon to OPAC lists page

Bug 25211: Add missing share icon to OPAC lists page

This patch adds a Font Awesome icon to the "Share" links on the list of
lists in the OPAC.

To test, apply the patch and log in to the OPAC as a user who has one
or more private lists.

  - Go to Lists -> Your lists
  - In the table of your lists, each list should have a "Share" link
    with an icon.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>