Bug 32173: Add list count to shelves.tt

Bug 32173: Add list count to shelves.tt

To test:
1. Build a list and look at it in the staff client.
2. No indication of how many items are in the list.
3. Apply patch and look again
4. You should see "This list contains x titles"

Signed-off-by: Barbara Johnson  <barbara.johnson@swbell.net>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 2790faf62ea434f7e47f9742f7bea54dcddcf46b)
Signed-off-by: Jacob O'Mara <jacob.omara@ptfs-europe.com>