Support for metering Firewall as a Service

We need to be able to monitor the usage metrics around Network Services ( FWaas, LBaas and VPNaas ). This blueprint targets requirements around the FWaas and see whats feasible.

* Firewall as a Service
- type of firewall ( iptables, CSR virtual firewall etc) - billed differently based on type
- Firewall usage in hourly increments
- Associate policies to permit or deny traffic, different from security groups (vm level)
- # of connections/sec
     - for cisco firewall we could get it from firewall itself
     - for iptables we might have to look at the router (might need a transformer)
- Bandwidth