Support in UI Airlock File uploads and downloads.

[fortunkam]

Is your feature request related to a problem? Please describe.
The Airlock process currently uses Storage SAS tokens for uploading and download files. This causes issues in highly regulated environments where SAS token (and shared key) access needs to be disabled on storage accounts.

Describe the solution you'd like
Would be nice to be able to Upload and Download files to the UI via the Airlock request pages. The solution would need to happen in the browser to preserve the networking constraints (e.g. You should only be able to upload to the import external storage account if you have network visibility to it)

Describe alternatives you've considered
Having up files uploaded via the API won't work because it breaks some of the networking constraints and there is a 2GB limit for file upload requests to an API in most browsers.