Allow editor to "accept" and edit question before "move to review"

Context

Current workflow:

Proposal

Editors want to the option of editing a item to fix something in the text or add additional metadata before it goes to a reviewer. So instead of moving directly to review (shown in green above), allow editors to accept --> optionally edit --> then move to review.

Design

Implementation (if applicable)

This means adding a new stage to the editorial lifecycle. The new status will be "Accepted", and will come after "Submitted". So the new editorial lifecycle will be:

0. Not Submitted (author can edit)
1. Submitted (read-only)
2. Accepted (ME can edit and move to review) or Rejected (read-only, end of lifecycle)
3. Under review (read-only, reviewer can submit feedback, ME can move to production or reject)
4. Production (ME and production team can edit)
5. Published (read-only, discoverable in Browse Items)
6. Unpublished (read-only, ME can move item to production to edit and republish)

Alternative approaches (if applicable)

Scheduling