Option to wait for interface selection before displaying firewall rules
The default behaviour of firewall_rules.php is to load all firewall rules on the WAN interface if no interface has been previously selected. When a large number of WAN side port forwards/firewall rules, etc exist, loading these rules can put a lot of load on the firewall. On a sufficiently loaded firewall this can actually impact packet forwarding, sometimes leading to packet loss.
It would be good to have an option similar to what exists for viewing state table entries(https://github.com/pfsense/pfsense/commit/88081ea257fa683ed28b588c4c35260589604741), requiring the interface to be set before loading the firewall entries.
I've already added a pull request with this feature https://github.com/pfsense/pfsense/pull/4582