Bug 25771: Allow the user to sort checkouts by the renew column in the OPAC

Bug 25771: Allow the user to sort checkouts by the renew column in the OPAC

This patch makes it possible for the logged-in OPAC user to sort their
checkouts by the number of renewals they have remaining on their
checkouts.

To test, apply the patch and log in to the OPAC as a user with multiple
checkouts. To fully test the patch's functionality the user's checkouts
should have a varying number of renewals available.

On the "your summary" page, confirm that the "Renew" column is now
sortable and that it sorts correctly by the number of renewals left on
each checked-out item.

Signed-off-by: Henry Bolshaw <bolshawh@parliament.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>