Multiple Cluster Networks: IP routes

Adds new attributes 'is_default_route' and 'other_nets' to
 l23network::l3::ifconfig.

Adds ability for ns_IPaddr2 to consume other_nets

In multiple cluster networks it is necessary for interfaces each have their
 own gateway. This adds 'is_default_route' so that only one interface will
 receive the default gateway route. This is assured by nailgun.

It is also necessary for each interface to know the route to the other
 networks of the same network role from other NodeGroups in the cluster. These
 networks are expressed in 'other_nets' and with the 'gateway' and interface
 name will be used to add routes to the node

data used from asute.yaml

Neutron network provider:
network_scheme:
  endpoints:
...
    br-fw-admin:
      IP:
      - 10.108.47.3/24
      default_gateway: true
      gateway: 10.108.47.1
      other_nets:
      - 10.108.52.0/24
    br-mgmt:
      IP:
      - 10.108.49.2/24
      gateway: 10.108.49.1
      other_nets:
      - 10.108.54.0/24
...

Nova network provider:
network_data:
...
  eth1:
    default_gateway: true
    gateway: 10.108.48.1
    interface: eth1
    ipaddr:
    - 10.108.48.4/24
...

Adds disabled code to configure haproxy to keep vip points together
 There are some deployment cases where the deployer may need to
 enable this and this serves as the code example to perform it.

Resolves-bug #1272766
implments: blueprint multiple-cluster-networks

Change-Id: I06e09fd9b292cac53b925933006de064e725bdb0
Merge "Multiple Cluster Networks: IP routes"