This helps large deployments which need to open up thousands of ports
(matrix_coturn_turn_udp_min_port, matrix_coturn_turn_udp_min_port)
On a test VM, opening 1k ports takes 17 seconds for Docker to "publish"
all of these ports (setting up forwarding rules with the firewall, etc),
so service startup and shutdown take a long amount of time.
If host-networking is used, there's no need to open any ports at all
and startup/shutdown can be quick.
aafa8f019c