FEATURE: PCI-337 - Do not mask Public IP at PrivateCloud behind the Firewall

Floating IPs from "public" pool:
* IN traffic - Public IP,
* OUT traffic - IP address of Firewall (NATed)

Floating IPs from "elastic" pool:
* IN traffic - Public IP
* OUT traffic - Public IP
Merge pull request #2 from gooddata/jpu-elasticips

FEATURE: ElasticIPs and PublicIPs pools