Workflow consistency with Edge and Distributed NAT

[Thomas Bachman]

The Distributed NAT workflow uses .ini file parameters to describe the IP addressing for external segments:

cidr_exposed = 1.103.2.254/24
gateway_ip = 1.103.2.1

These are the IP addresses represented at the edge of the network (i.e. leaf node) when NAT is used.

The Edge NAT workflow currently uses these IP addresses to represent the "transit" network (the network between the ACI leaf and the ASR). This should be changed so that the IP addresses are on the edge of the network in the ASR case as well -- making the two workflows semantically equivalent. This would require the addition of parameters in the .ini file to describe the IP addresses used on the transit network.