Bug 8435: add permission to enable editing other library's serials if IndependantBran...

Bug 8435: add permission to enable editing other library's serials if IndependantBranches is on

In the serial module, we want to hide serials from others libraries.
However, to permit central serials manage, this patch introduces a
new permission, 'superserials'. If a staff member has this permission,
that person can override the restriction.

Test plan:
- Switch on the IndependantBranches syspref
- Add the permission 'superserials' for a patron and test you can
  navigate and see all serials
- Remove this permission and test you cannot manage/view subscriptions
  from others libraries

Signed-off-by: Frederic Durand <frederic.durand@unilim.fr>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>