Move Fieldmapper API call to Application.pm

Move Fieldmapper API call to Application.pm

Move export of opensrf.open-ils.system.fieldmapper API call from
Fieldmapper.pm into Application.pm with the rest of the shared API
calls.  This allows us to remove the OpenSRF::Application base from
Fieldmapper, which was causing some method name collisions.  For
example, if a Fieldmapper object had a field called "session", which,
incidentally, is also a method of OpenSRF::Application, the version
from OpenSRF::Application would get called instead of the Fieldmapper
version, since Fieldmapper methods are defined during AUTOLOAD.
Hilarity was guaranteed to ensue.

Signed-off-by: Bill Erickson <berick@esilibrary.com>