Interface-dependent handling of pi.hole and the machine’s hostname
This makes FTL automatically reply with the appropriate IP address to both pi.hole and the machines hostname. Before this change, FTL always used a hard-coded address set during the weekly gravity updates (pihole -g). The new method is interface-aware and may reply with different addresses on different interfaces (e.g. Ethernet, WiFi or Wireguard network). The address FTL replies with can be overwritten using the REPLY_ADDR4/6 settings in /etc/pihole/pihole-FTL.conf.