When fronting the playbook's integrated Traefik reverse-proxy with
another reverse-proxy (e.g. nginx), WebSocket traffic needs to be
forwarded to LiveKit Server at the `/livekit-server/` path for Matrix
RTC calls to work.
Adds a `/livekit-server/` location block to the nginx reverse-proxy
example, a section to the Matrix RTC docs explaining the requirement,
and cross-links between the two.
* update http2 config due to deprecation
the previous way to let `http2` follow a `listen` was depracated, it
moved to `http2 on;`
* enable quic and http3
I hope the comments are somewhat understandable. if someone can describe
the `reuseport` part more concise, please do.
