[package] firewall:

	- fix processing of rules with an ip family option
	- append interface rules at the end of internal zone chains, simplifies injecting user or addon rules
	- support simple file logging (option log + option log_limit per zone)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@22847 3c298f89-4303-0410-b956-a3cf2f4a3e73