Document Manager; updated handling of files stored in the Bulk folder

The Files page shows all Files located in the Account, Client etc folder plus any located in the corresponding "(Bulk)" folder that are referenced via a Log.

These were shown with a File Category of "(Bulk)", but this was confusing. Now the Category is shown as blank and the File Name is prefixed with "..\(Bulk)\".

In addition, you could delete and rename files located in the Bulk folder, which should not have been possible.

Changes to the Business Layer include:

• A new Boolean "IsBulkFile" has been added to finDocumentFile.
• finDocumentFiles CanDelete and CanRename functions have been updated to stop these actions on Bulk Files.