feature request: add output chain

[OneOfOne]

It'd be nice to have an output chain with reject as well.

	chain output {
		type filter hook output priority filter -1; policy accept;
		ip daddr @blacklist-v4 counter reject;
		ip6 daddr @blacklist-v6 counter reject;
	}

[tomasz-c]

Would such a chain also be useful to others?
In my opinion, it does not seem to be needed. Unless for some hosting services.

[tomasz-c]

I added optional blocking output connections to blacklisted IPs in commit b20de77
This feature was published in the release 1.1.0