Bug 11976: Add Publication date to subscription table (opac) + column settings

Bug 11976: Add Publication date to subscription table (opac) + column settings

This patch adds the column settings feature to the subscription list at
the OPAC.
It also adds a new column (Publication date) to this table

Using Home->Administration->Column Settings->OPAC->subscriptionst
the fields visibility can be toggled.

TEST PLAN
---------
1) Have a subscription where you have received at least once.
2) Look for it in OPAC and note the date is the received date, not the publication date
3) Apply patch
4) Log in to staff client
5) Home->Administration->Column Settings->OPAC->subscriptionst
6) Set visibility as desired.
7) Refresh OPAC page
   -- everything should be as expected.
8) run koha qa test tools.

Signed-off-by: David Bourgault <david.bourgault@inlibro.com>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>