Bug 18403: Patron discharges

Bug 18403: Patron discharges

This patch deals with patron's discharges.

Test plan:
Same as previously you will need to request dischages at the OPAC.
On the staff interface the logged in user should not be allowed to see
discharge
from patrons outside his library group.
The number of discharges waiting displayed on the mainpage should be
correct as well.

Signed-off-by: Signed-off-by: Jon McGowan <jon.mcgowan@ptfs-europe.com>
Bug 18403: (follow-up) Patron discharges

Fix QA issue:
forbidden pattern: Do not assume male gender, use they/them instead (bug 18432) (line 150)

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>