LP#1849736 Add action trigger for email/sms for patron self registration

LP#1849736 Add action trigger for email/sms for patron self registration

Setup a new A/T Hook.

Includes:
1. New row in action_trigger.hook
2. New row in action_trigger.event_definition
3. New clause in action_trigger_filters.json.example
4. Link XML clause for oils_obj:fieldmapper="staging::user_stage" on fm_IDL.xml
4. pgTAP Test
5. Release Documentation

Signed-off-by: blake <blake@mobiusconsortium.org>
Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>