Allow previewing download links

User story

Before publication, when proofing an article, I may want to check if the file download links work. I may not be sure if they point to the right versions of the files. Or I may not be sure that I uploaded them properly and want to be sure before I publish the article.

Currently, I can't do that when previewing the article page, because journal.views.view_galley and journal.views.download_galley check if the article is published and return a 404 if it isn't.

Janeway version

1.7.3

Proposed solution

• Alter these views (download_galley and view_galley somehow so that it considers whether the article is being proofed, and returns the appropriate file if so.
• Remove these notes to proofreaders in the templates, as they will no longer be accurate:
  https://github.com/openlibhums/janeway/blob/d9e6837a9e6bceff89446dd48debf2268b19d605/src/themes/OLH/templates/journal/article.html#L368-L373

Start with journal.views.view_galley and journal.views.download_galley, which currently return 404 responses for unpublished articles. Then inspect the article template at src/themes/OLH/templates/journal/article.html around lines 368-373. Done means proofed articles can preview and download the appropriate files, and the outdated proofreader notes are removed.