Bug 7567: convert news add/update routines to take hashref; fix bugs

Bug 7567: convert news add/update routines to take hashref; fix bugs

Changed the add and update functions to use a hash reference
for the parameter, so that adding or subtracting parameters
should be easier. Added some POD for the add_opac_news and
upd_opac_news functions, so that developers would know how to
call it.

The hashref changes resulted in being able to return 0 for
failure and 1 for success. This meant adding a couple tests
to the test file.

And while testing, there was some sort of logic problem with
the matter of '' being all, but selecting all only showed
things set for all, and excluded particular languages, or other
interfaces.

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>