Bug 10245: add CSS classes to OPAC detail items table header

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Classes now appear on <th> as well for easy styling.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Passes koha-qa.pl, template changes only. Adds classes and id's to table
headers, makes no other changes.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>