Bug 9167: Standardize the sort field copyrightdate for lists

Bug 9167: Standardize the sort field copyrightdate for lists

How to reproduce the issue:
Create a list at the OPAC and select the sort field 'year'. Go to the
list management page at the intranet: the sort field "copyrightdate" is
not selected by default.

How to test this patch:
Check the issue is not still present with this patch.
Create several lists at the OPAC with different sort field.
Check results are consistent on both interfaces.
Check the selected sort field is selected on the edit page.
Check there is no regression.

What this patch does:
- change the way to send the selected sort field to the templates
- remove the select tests on the new list page (useless)
- the copyrightdate sortfield is named "copyrightdate" everywhere
- update your database : set virtualshelves.sortfield = 'copyrightdate'
  if virtualshelves.sortfield = 'year'

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Works as advertised. Improves code.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>