Add notification log to JSM issues

JSM Cloud painfully lacks customer-facing email logging. Agents respond to customers from within an issue with email, but have NO IDEA whether those messages ever reach their intended target. There is damage to reputation, effectiveness, and relationships. 

Atlassian keeps 2-3 weeks of email logs before dumping them, but each instance must be accessed with a unique support request.

JSDCLOUD-4698 "Provide outgoing email logs" has been active for FOUR YEARS with strong demand and ZERO results. 

SUGGESTION = Show status for each message in the issue (ticket) layout, perhaps in the History tab or a new Notification tab.