WIP: testing infrastructure + caching for nginx + hopefully some bugs fixed in the process

See this branch in action here:

Directly on the lag server: https://hlsorigindev.laglab.org/player/hlsorigin.html Behind a cache: https://hlsdev.laglab.org:8443/player/cached.html

To play with it, login to fresh.lag, its in /root/sources/streaming-docker