Adds support to seperate Swift access and replication traffic from other storage traffic.

In a deployment where both Ceph and Swift have been deployed,
this changes adds functionalality to support optional seperation
of storage network traffic. This adds two new network interfaces
'swift_storage_interface' and 'swift_replication_interface' which maintain
backwards compatibility.

The Swift access network interface is configured via 'swift_storage_interface',
which defaults to 'storage_interface'. The Swift replication network
interface is configured via 'swift_replication_interface', which
defaults to 'swift_storage_interface'.

If a separate replication network is used, Kolla Ansible now deploys separate
replication servers for the accounts, containers and objects, that listen on
this network. In this case, these services handle only replication traffic, and
the original account-, container- and object- servers only handle storage
user requests.

Change-Id: Ib39e081574e030126f2d08f51de89641ddb0d42e