LP1858213 A/T require email and stamp user id

LP1858213 A/T require email and stamp user id

Add require_usr_email flag to action_trigger.event_definition.  When set
and a usr_field is defined, only events for users with email addresses
will be created.

Adds a new column to action_trigger.event for tracking the related user
id.  At event collection time, if an event_definition has a usr_field,
the id value is added to the event.

Includes updates to set 'usr_field' values for existing event
definitions where possible and to set the require_usr_email flag for
SendEmail defs that have a usr_field.

Signed-off-by: Bill Erickson <berickxx@gmail.com>