Bug 15044: Add date suggestion to OPAC suggestions table

 Bug 15044: Add date suggestion to OPAC suggestions table

To test:
1) Log in to OPAC, go to your purchase suggestions (opac-suggestions.pl)
2) Confirm there is now a 'Suggested on' column displaying the date of your past suggestions
3) Add a new purchase suggestion and confirm that the date displayed is correct

Sponsored-by: Catalyst IT
Signed-off-by: Marjorie <marjorie.barry-vila@ccsr.qc.ca>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>