Upload audio and video files to content archive

This should close #98
SD-113 Upload video files to content archive
SD-161 Upload audio files to content archive
This is according to requirements, I can remove the check for "required" but then we have to be sure that this is properly set from front-end.
From SD-113:
2- I can upload a video by entering the following information: a) title and b) file. Where both fields are mandatory. The File field refers to selecting the video file from my computer.