Ahodges/video upload

Initial draft of the "Processing Video Files" guide for consortium members describes the procedures needed to get an institution up and running (video_prereqs.rst) and for course teams to upload video files (video_uploads.rst).
An HTML version is available at http://draft-processing-video-files.readthedocs.org/en/latest/
@nasthagiri, @frrrances please review video_uploads.rst in particular.
@lou-wang, @srpearce please review from your knowledge bases. 
@mhoeber, @catong FYI.
Sending HTML link to Greg Martin and Rachel Grubb also. Please tag any other reviewers as appropriate.
Rachel would like to begin sending the HTML link to interested course teams ASAP.
As we talked, remove 2.6. Enable Video Upload in Studio