Configuration agent for Cisco devices

A generic config agent for configuring L3+ services in Cisco devices.

This patch targets specifically configuration of L3 fuctionality,
namely routing, NAT and floatingIPs in Cisco CSR1kv virtual appliance.

Implements blueprint: cisco-config-agent
https://blueprints.launchpad.net/neutron/+spec/cisco-config-agent

Change-Id: Ic887a93480eca0b56049c67e32c98658e3a4427f
Merge "Configuration agent for Cisco devices"