Nginx HTTP 2.0 issues

[lukefor]

https://jellyfin.org/docs/general/networking/nginx.html

The example specifies http2, however this caused some platform-specific issues for me in conjunction with the Jellyfin-Kodi plugin:

• Kodi 19.3 on CoreELEC randomly failed to load fanart and episode images
• Kodi 19.3 on Amazon Fire Stick unable to stream anything for long without buffering or terminating playback at random

Other platforms such as Kodi 19.3 on Android 5.1 and Kodi 18.x on Windows did not exhibit these issues. All issues were resolved when http2 was disabled

I suggest to add a warning about usage of Jellyfin+Kodi with http2 (it must be disabled for all server blocks per IP/port, not just for Jellyfin) and removing it from the example