Ability to set acceptable file types in WORKFLOW MANAGEMENT/File types

[labuchholz]

Is your feature request related to a problem? Please describe.
Some of our students are uploading Word documents in the Manuscript in PDF document type. These get renamed, as expected, per configuration in application.yml. However, the renaming process also changes the extension to ".pdf". When we download and try to open the files, PDF applications say the file is corrupted. Replacing the file extension with ".doc" allows the file to open in Word without any issues.

Regardless of the renaming issue, we don't accept Word documents, and would like to be able to limit submissions to PDF files only.

Describe the solution you'd like
We would like the ability to set the Manuscript in PDF file type (in WORKFLOW MANAGEMENT/File types) to only accept PDF files. If the user uploads a file that is not a PDF, they should get a failure notification with a clear message, for example "file type not supported, please upload a PDF" or similar.

Describe alternatives you've considered
A sort term solution would be to only rename the base filename, and leave the extension as is. This would allow us to spot .doc files in List view, with the Manuscript in PDF column.

Additional context
We do want the files to be renamed, so don't want to turn off the setting in application.yml