Bug 7720: add options for controlling display of an item's home and/or holdings location

Bug 7720: add options for controlling display of an item's home and/or holdings location

Currently, in opac-detail.pl, there exists a column named 'Location'.
This column lists the name of the holding branch, and the item's
location description. This can cause confusion to borrowers, as
they may assume that the holding branch is the *owning* branch
(homebranch) of an item.

This could cause a situation where a borrower waits for an
item to be returned to his or her library, only to find that
the library never owned that item, and it was transferred back
to its homebranch. It could also lead a borrower to falsely
assume that his or her home library does not own a copy of a
particular item because the borrower does not see an his or her
home library listed for any of the items on the record.

In addition, even when the holding branch is different
than the home branch, the item's shelving location is displayed,
even though that branch may not use that location.

This commit makes the item details table equivalent to the intranet
details page by adding a "Home Library" column, which displays the
item's home library, as well as the shelving location.

If singleBranchMode is enabled, this column disappears and the
"Location" column displays the shelving location only.

This commit adds two new system preferences:

OpacLocationBranchToDisplay, which defines whether
to display the holding library, the home library,
or both for the opac details page.

OpacLocationBranchToDisplayShelving, which defines
where the shelving location should be displayed,
under the home library, the holding library, or both.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Comment: Work as described. Tested all variations.
No koha-qa errors.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>