Author can edit their items after submitting them

Context

From conversation in #425 (comment 147621)

Apologies @DioneMentis, I am making a note here to adjust my request. We will also discuss this ticket during our meeting to make sure the ask is clear.

1. Author creates a new item and Submits it for review.
2. Author duplicates that submitted item, makes edits, and then submits new item (which is a duplicate) for review.
3. An email notification is sent to the reviewers when the author submits the new edited item that was created from making a duplicate of a previous question.

Proposal

Allow an author to make edits to their questions after submitting them and before the item is accepted by the editors.

1. Add edit button visible only to authors when the item is in the 'submitted' stage
2. Clicking the button makes the item editable, and blocks the editors from accepting it
3. When author resubmits, the item moves back to read-only, and the editors receive an email about the update
4. Afterwards, editors can accept the item and move to the next editorial stages the same way as it works now.