Firewall improvements

[nervetattoo]

This adds two improvements to the firewall setup:

1. Manage iptables rules better by not blindly appending the same rules over and over on each firewall update. Uses ansible_iptables_raw to handle the rule insertion
2. Set up rejection logging for the firewall onto /var/log/iptables.log via rsyslog with logrotate conf

[nervetattoo]

Updating fw after this change will work, but append a new rule. The second time and forward you run it though, it will not append a new rule.

The old rules would have to be manually removed, I don't see how they can safely be removed scripted

[frankscholten]

Awesome! Thx @nervetattoo