Redo VoD upload

[joschahenningsen]

The current state of the VoD upload is:

• Broken
• Videos are uploaded to TUM-Live and then uploaded to the LRZ (From the same server that hosts TUM-Live and without any verification regarding the uploaded files)

I imagine either of these scenarios:

1. TUM-Live generates a token for VoD uploads when visiting the EditCourse page
2. The user posts the video directly to a worker, combined with a token
3. The worker notifies TUM-Live about the job
4. TUM-Live creates the lecture with the state pending, converting or similar
5. The Worker verifies the codec of the video file and (if needed) converts it and moves it to our ceph storage
6. The Worker uploads the video
7. The Worker notifies TUM-Live that the video is ready

Alternatively:

• TUM-Live receives the video and drops it off somewhere in the ceph storage
• TUM-Live creates the lecture with the state pending, converting or similar
• TUM-Live notifies a worker about the job
• like above from point 5 onwards

I'd like to have #369 merged first