Firewall rule tweaks

[plotnick]

A few things are missing or need tweaks in the firewall rule add/edit forms. Noticed while plumbing firewall rules.

• Missing Ip and IpNet target types.
• IpNet host filter type is missing (e.g., 1.1.1.1/8).
• InternetGateway is available as a host filter type, but not supported by the back-end.
• Action and direction are not pre-selected when editing an existing rule.