Improve mp4 streaming

[andreibosco]

• https://subscription.packtpub.com/book/networking_and_servers/9781849514965/9/ch09lvl1sec109/streaming-of-mp4-h-264-files
• https://nginx.org/en/docs/http/ngx_http_mp4_module.html
• https://github.com/kaltura/nginx-vod-module

[andreibosco]

For deployment, static/media files are now being handled by S3.