设置 Linux 防火墙规则，以允许 Fuchsia 设备和模拟器流量。
Setup Linux uncomplicated firewall (ufw) to allow Fuchsia device and emulator traffic.
This command detects whether an active Linux firewall service is setup,
and if so, will add special rules to allow Fuchsia-specific traffic to
go through the link-local IPv6 network interfaces used by Fuchsia devices
and emulators.
NOTE: This script uses sudo and will thus ask for your password!
-n|--dry-run Just print all steps, don't do any configuration