Copy MediaSpace (and Box?) access restrictions.

MediaSpace uses an ActiveDirectory check using a Tag string, to check if a user is enrolled in a course. We could support these tags too (at least for UIUC user).

Secondly, Mediaspace access to a video could be more restrictive than ClassTranscribe's access settings. Warn the instructor if this is true.

Note there are times when the instructor wants the video availability to be different on the two platforms e.g. private on MediaSpace but more open because they want the analytics of ClassTranscribe, and so want students to use ClassTranscribe.