Fill additional JIRA fields based on commit message

Zendesk issue: https://gitlab.zendesk.com/agent/tickets/15489

The customer wants GitLab to fill additional JIRA fields such as 'Reviewed by', 'Resolution description', and 'Testing instructions'. They've modified a community Java standalone service to do this. They've attached the code in the Zendesk issue for us to reference.

On the surface it seems reasonable but more digging is necessary to see exactly how we can do this.

cc/ @JobV