LP#1356477: add ability to unconditionally send email

LP#1356477: add ability to unconditionally send email

This patch defines and uses an
open-ils.trigger.event.autocreate.ignore_opt_in method that does what
it says on the tin; the caller is reponsible for not abusing this.

This supports a use case in the webstaff checkout interface where staff
can choose to have the receipt be emailed, provided that the patron
record has an email address defined, even if the user setting to
email receipts by default is not set. (It is assumed that the staff
member would have gotten permission from the patron on the spot.)

Signed-off-by: Galen Charlton <gmc@esilibrary.com>