Bug 34292: (bug 33804 follow-up) Format "checked out on" date

Bug 34292: (bug 33804 follow-up) Format "checked out on" date

Test plan:

1) Without applying this patch, issue an item to a patron and
   notice that in the 'Checkouts' table the 'Checked out on'
   date is of the form YYYY-MM-DD HH:MM:SS.

2) Apply this patch, restart Plack if necessary.

3) Refresh the patron 'Checkouts' table: this time the 'Checked
   out on' date will observe the setting of your `dateformat`
   System Preference.

4) Extra credit: repeat step 3) for different `dateformat`
   settings, each time you should get a 'Checked out on' date
   that matches the date format you chose.

Signed-off-by: Andreas Roussos <a.roussos@dataly.gr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>