Bug 26274: Update register.tt to use the API

Bug 26274: Update register.tt to use the API

This patch updates the existing register details page to utilise the new
api routes to gather the summary details on demand.

Test plan
1/ Enable cash registers
2/ Add some transactions
3/ Perform a cashup
4/ Click 'Summary' next to the last cashup date
5/ Note the modal appears as it did prior to the patch being applied.
6/ Check the print option still works
7/ Signoff

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>