Set upload_image policy to control data upload

There was no policy to control data upload.
Up until today, the add_image policy was a all or nothing, from metadata
to the actual data. Now, with the combination of add_image and upload_image
an administrator will have finer control over the whole chain.

Change-Id: I1a7966ffb5c63dd8239a54fe2963b031d9fe1f9a
Closes-bug: #1254521
Merge "Set upload_image policy to control data upload"