Support Load Balancer multiple IP setting

[FinalDoom]

pfSense supports multiple IPs as a comma separated list (UI anyway..) https://redmine.pfsense.org/issues/10896

Instead of grabbing first load balancer IP, use them all in pfsense.

This might be related to an issue I'm seeing where it is always registering changes and restarting DNS every polling period, but not sure.

Will submit PR, open to making this a setting somewhere but haven't looked into how that works yet.