[CoLab] Add ability for editor to rescind reviewer invitation
Currently, a reviewer's access to a review page can be revoked by deleting the reviewer from the Control panel>Manage reviewers page. It is not currently possible to revoke a 'reviewer invitation' email notification.
Solution; a 'delete' action should also be available in the Control panel once the email notification is sent. This feature can be used by the editor to rescind the invitation.
The email notification may have still been sent, but clicking on the accept/decline should not display a notification that access to the review has been revoked.
Current state, control panel does not include a 'delete' (rescind) action;