Provide a way to create media from file already in Fedora

[mjordan]

Following up on the discsussion at the very end of today's Islandora Online IR session, to support very large files, it would be useful to provide a way to create a media from a binary resource that has already been uploaded into Fedora. This is based on the assumptions that Fedora can handle much larger file uploads that Drupal can. The end user UX for this would probably suck, but the admin user UX could be paste in the Fedora URL to a binary resource and Bang! you've got a media that is indistinguisable from one that was created by uploading the file to Fedora through Drupal.

Tagging @rosiel since she also thought of this workflow.