Add media types for HLS and MPEG-DASH
Add media types for HLS and MPEG-DASH

The originally registered media type for .m3u8 is
application/vnd.apple.mpegurl, but the de facto standard of the past
several years is application/x-mpegurl, and this is what Apple
currently recommends.

ring-clojure/ring,ring-clojure/ring