[Sync] Track the 'reporter' field on JIRA issue records

[jstanden]

We should probably discuss if we want to normalize reports to a jira_user table and do jira_issue.reporter_user_id, or just put strings in a jira_issuer.reporter_name field. The reporter field will be useful to track the origin of feedback, although I avoided it up to this point because we'll probably start taking a lot of feedback entry from the website via the API w/ the 'Cerb' user as the reporter. We'd have to track actual reporters a different way -- and it may only matter that we're tracking someone's interest in something (like watchers) instead of caring who opened a request.