Add route to get video status

[RaboliotLeGris]

Have a route that look like:
GET /api/v1/videos/{ID}/status and it returns the state of the video.

Proposition of states: Missing / Uploaded / Processed

Missing -> Get try to find the folder or the source of the video by it's ID and it doesn't exist
Uploaded -> The folder and the source exist (ID/source.extension)
Processed -> A file Ready.txt exist on the S3 (ID/Ready.txt)