Bug 6647: Label item search should use standard pagination routine

Bug 6647: Label item search should use standard pagination routine

This patch doesn't fix how pagination links are generated for the label
item search results, but it does modify the template so that the
pagination links are styled like they are on catalog search results.

To test, apply the patch and go to Tools -> Labels.

 - Open or create a label batch.
 - Click "Add items" to trigger the pop-up search window.
 - Perform a search which would return multiple results.
 - Confirm that the style of the pagination bar matches the one on the
   catalog search results page.
 - Confirm that current-page number highlighting works correctly.

Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>