Updated Avahi service configuration to support both IPv4 and IPv6 addressing. This change includes enabling nssmdns4 and nssmdns6, along with setting ipv4 and ipv6 to true.
Enabled the Syncthing service in the fileserver configuration. Set the user to 'harald' and specified directories for data and configuration.
Signed-off-by: Harald Hoyer <harald@hoyer.xyz>