[WIP] Initial iptables setup

:construction_worker: Throwing this out there for #307. This is a work in progress and needs further refinement.

* [X] iptables rules for web servers
* [ ] iptables rules for Jenkins
* [ ] Disable all access on IPv6

There are some major issues I see with getting this locked in the way we want:

* Provisioning happens in 3 segments, we can't use that information to apply rules related to Jenkins (allow SSH to the web server from the Jenkins box)