Reports API has too many unnecessary report status types

[jwr1]

At the moment, the api docs say that the GET /api/moderate/magazine/{magazine_id}/reports route could return any one of these report status types: appeal, approved, closed, pending, rejected. While using the Mbin web client, I've only ever seen reports with the pending, approved, or rejected status. It doesn't seem there's any way to "appeal" a report.

I was hoping we'd be able to remove the appeal and closed report statuses from the API. ATM, it seems once a report is approved through the API, that it changes the status to closed, when it should change it to approved. I also noticed when I ran a DB query (select distinct status from report;), that almost all reports were either approved, pending, or rejected. Weirdly, there were three single reports that had a status of closed.

So, to reiterate, I think we should clean up the report code to remove the "appeal" and "closed" status types, both in the API and in the DB.