Bug 24585: Add 'Managed on' and 'Suggested on' columns to pat_purchase_suggestions.tt

Bug 24585: Add 'Managed on' and 'Suggested on' columns to pat_purchase_suggestions.tt

This patch adds 2 new columns on the suggestions table on purchase-suggestions.tt. These use the data-order attribute to allow for sorting.
TEST PLAN:
1. Have a patron with some suggestions that have been managed by staff. (accept or reject the request).
2. View that patrons suggestions from purchase-suggestions.pl.
3. No suggested on or managaed on columns.
4. Apply patch and reload the page.
5. The new columns are there, have multiple suggestions and make sure sorting by the date works.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>