firewall: Fix creation of automatic rules for the firewall.

If the firewall is part of a local network (e.g. GREEN),
we automatically add rules that grant/forbid access for the firewall,
too.

This has been broken for various default policies other than ALLOWED.
firewall.cgi: Sort protocols alphabetically.
rules.pl: Rewrite P2P protocol filter.
firewall: Change headlines for rule sections.
firewall: Fix spelling and seperate spelling issues.
firewall: Fix outgoing OpenVPN N2N tunnel packets.

Don't throw away packets from the firewall that pass through
an OpenVPN N2N tunnel.