Add Firewall Rules for Both Wireless and Ethernet

This is meant to adress #7 and replaces `NET_DEV` with `NET_DEV_ETHERNET` and `NET_DEV_WIFI` and adds/deletes firewall rules for both of them. I figure its best to do both instead of just the active one in case of switching (if I unplugged my ethernet cable, it would automatically switch to wifi and vice versa). I also added them to the man page.