Keep track of video ids after upload

[ldang]

Currently, the splitting and upload of the videos is done separately from the webapp.
It would be nice if we eventually store the URL for the videos after they have been uploaded, so they can be viewed from the webapp.

That would make the following easier:

• Track leads would be able to easily see the individual videos for their track and communicate that to their speakers
• It would make it easier for us to embed the video into the approrpiate talk page on the SCALE website

And it would help with a future enhancement of making automatic playlists.