[Infrastructure] [Firewall] Initial UFW provisioning

:construction_worker: Throwing this out there for #307. This is a work in progress and needs further refinement.

* [X] iptables rules for web servers
* [x] iptables rules for Jenkins
* [x] 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)

I suppose we *don't* want to specify `direction=in` here because Jenkins also needs to SSH out, correct?