initial solution, but found related bugs

[StephDriver]

addresses #3746 but further issues found, and when tested, same behaviour was seen on master.

• production files are marked as manuscript files
• proofing files cause an apparently infinite loop of uploads, when test-server is halted, the file is found to have been uploaded multiple times.

to replicate issues:

1. go to document manager
2. upload a proofing file or a production file.

[StephDriver]

new upload errors found are now listed at #3851

Closes #3746

[StephDriver]

The changes requested will be easier on a new branch off current master than to further change this very old branch. So closing this.

[StephDriver]

This PR has now been superseded by #4292