Implement Allowed Address Pairs

The following patch adds the concept of allowed address pairs.
This allows one to add additional ip/mac address pairs on a port to
allow traffic that matches those specified values. This is useful in order
to leverage dataplane failover mechanisms like vrrp. This patch adds support
for the NVP plugin, the OVS plugin, and Ml2.

DocImpact

implements blueprint: allowed-address-pairs

Change-Id: Ie73b3886c5be8e1fc4ade86a0cfb854267f345ac
Add sub-type field to VXLAN network profiles for Cisco N1KV plugin

Rename VXLAN type of network profiles to Overlay network profiles.
Add a new sub type column to Overlay network profiles. Support
enhanced VXLAN and native VXLAN as Overlay sub types. Allow plugin to
be flexible to support newer sub types.

Change-Id: I3899b01f316902d1139e47b153a9db7ecb3ff982
Implements: blueprint cisco-plugin-n1k-enh-vxlan-support
Merge "Implement Allowed Address Pairs"
Merge "Add sub-type field to VXLAN network profiles for Cisco N1KV plugin"