Bug 22624: Show OPAC description for authorised values in OPAC

Bug 22624: Show OPAC description for authorised values in OPAC

Patch adds the IS_OPAC parameter to a few GetByCode calls in
OPAC files.

To test:
- Add different OPAC and intranet descriptions to some authorised
  value categories:
  - TERM
  - DEPARTMENT
  - LOC
  - CCODE
- Create a new course using the values and adding items to it
- Check the course reserves overview and detail pages in OPAC
- Verify Department, term, location, and collection show
  the OPAC description if existing
- Create a subscription, make sure a default location is selected
- Check the OPAC detail page, subscription tab for this subsription
  in the OPAC
- Verify the location of the subscription displays correctly

Signed-off-by: Mikaël Olangcay Brisebois <mikael.olangcay-brisebois@inLibro.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>