LP#1610246 Classic Circulation View excluding circulations

LP#1610246 Classic Circulation View excluding circulations

The reporter.classic_current_circ view, which is available via
Open-ILS/src/sql/Pg/example.reporter-extension.sql, was excluding
circulations because it was assuming all users have a billing address
This branch corrects that with a LEFT JOIN.

No upgrade script will be included since these views are not assumed
to be installed by all Evergreen instances.  Please re-run the
example.reporter-extension.sql file to apply this change for your
instance.

Signed-off-by: Chris Sharp <csharp@georgialibraries.org>