Manage file uploads for document attachments

Value for user:
When adding a document to a license or agreement a user may wish to store a copy of the document in Folio as a file to make it easy to access the document when viewing the relevant part of the license or agreement.

Examples:

• An institution has a PDF copy of a signed & counter-signed license for an e-resource. They wish to store the PDF in Folio to make it easy for other users to access the information at a later date

Roles and restrictions:

• Any user who can manage (add/update/remove) a document attachment in a particular context should be able to manage (add/update/remove) an attached file in the document attachment

Workflow / UI expectations:
1. A user can manage file uploads from the document attachment element in edit panes for licenses and agreements
2. A user can upload a file within a document attachment
3. If the document attachment already has a file uploaded, uploading another file should replace the existing file. The user should be warned that uploading a document will replace the existing document
4. If the document attache already has a file uploaded, the user can remove that file. The user should be warned that removing the file is permanent

Business rules & constraints:

• A document attachment can have zero or one uploaded files