Set and enforce review statuses

    +----------+  reject   +-------------+
    | rejected | <-------- | no_response |
    +----------+           +-------------+
                             |
                             | accept
                             v
                           +-------------+
                           |  accepted   | -+
                           +-------------+  |
                             |              |
                             | autosave     |
                             v              |
                           +-------------+  |
                           |   started   |  | submit
                           +-------------+  |
                             |              |
                             | submit       |
                             v              |
                           +-------------+  |
                           |  submitted  | <+
                           +-------------+
Update submission state on save

If the submitted field is true, it becomes submitted; otherwise, it
becomes started.