LP#1566016: remove SSN as a stock ident type

LP#1566016: remove SSN as a stock ident type

This patch removes the SSN (Social Security Number) as a stock
patron identification type, as it is no longer recommended
practice for libraries to store SSNs.

To test:

[1] Verify that in a fresh installation of Evergreen that
    has this patch in place, that SSN is no longer listed
    as a patron identification type.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: Kathy Lussier <klussier@masslnc.org>