Allow for override of file upload/storage location through system configuration

[Chris-Schnaufer]

Task to do
Allow administrators of Atlana (DPP UI) disable default-upload-isolation mechanism

Reason
Right now, each user's server-side file system view is isolated from every other user's. The issue is to allow that behavior to be overridden with the following effects:

• mounted file systems, or existing server-side file systems, that are pre-populated with data are accessible to users
• all users upload files to the same location via the file upload mechanism (not workflow-related uploads)
• all users see all the files that are available

Result
The files available on the server are accessible, removing the requirement to (almost) always upload the files a user wants to use

*Other options
Require users to self identify and use that ID for isolating uploads and existing server-side files. This has the problem of adding/requiring a layer of authentication to the interface; potentially making it less portable and adding more complexity to Atlana (implementing credential management).

Notes
This has no impact on remote storage mechanisms, such as IRODS=