Bug 16464 - If a patron has been discharged, show a message in the OPAC

Bug 16464 - If a patron has been discharged, show a message in the OPAC

This patch adds a message to the patron home page in the OPAC to be
shown if the user is restricted because of a discharge.

To test, apply the patch and log into the OPAC as a patron who has been
discharged.
 - You should see a message which says so, including a link to
   the discharge notice.
 - Log in to the OPAC as a patron with a manual restriction and confirm
   that the correct notice is displayed.

Signed-off-by: Claire Gravely <c.gravely@arts.ac.uk>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>