Bug 20456: Switch routling list tab in staff to use Koha::Object

Bug 20456: Switch routling list tab in staff to use Koha::Object

Bug 20400 added a routing list tab to the patron account in the
OPAC using Koha::Object.

This patch switches the routing list tab in the patron account
in intranet over to the new code. It also adds an additional
column showing the position of the patron on the routing list
and fixes the search.

To test:
- Create some subscriptions with routing lists
- Take a look at the patron accounts of several patrons having
  - no entries on routing lists
  - 1 entry on a routing list
  - entries on several routing lists
- Make sure the display works correctly.
- Search for a subscription and make sure search works.

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>