Add new hook and view for initial approval of article for preprint publication

[ajrbyers]

• Add hook to the Unassigned page in Janeway
• Plugin registers for hook and inserts an action button
• Action button directs editor to a new view in the plugin where they can select the MS to generate the preprint with
• View will show the editor the PDF that will be published
• Finally allow the Editor to mark the preprint as published