Add configuration for other internal or remote subnets

Migrated from: https://tracker.clearos.com/view.php?id=96

Reported by: Dave Loper

Need to add the ability to add additional subnets other than just the default webconfig acl.

Comment 1:
ClearOS was not designed for multiple LAN segments or complex networks, so this feature has never been implemented in webconfig. It is possible to add these changes via the command line. See "Additional LAN Networks" in the following document:

http://www.clearfoundation.com/docs/howtos/managing_static_routes#additional_lan_networks

This feature would is (mostly) a side effect of implementing static routes (feature 0000097)

Comment 2:
It would be very good if this could parse the VPN configuration, as most companies using the hub and spoke VPN model with the proxy server will want the remote VPN subnets included for web access. I appreciate that having things automatically add is whole new level of complexity, and I would be more than happy to start with a GUI page to update the squid.conf.

It wouldn't be too much more to incorporate the !safe_ports part of the squid.conf file into a GUI page (again future scope for integration with firewall rule creation...).