Bug 28127: add transaction timestamp to register details tables

Bug 28127: add transaction timestamp to register details tables

To Test:
-Enable POS and setup some registers
-Make some transactions
-Go to Point of Sale > Register details and look at the two tables, sales and past sales
-No timestamp or transaction date
-Apply patch and look again
-See Tranactions dates in the Transaction column

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>