This will allow an operator to force the failover of a load
balancer's underlying amphora for upgrades or other
maintenance.
- Adds a new failover endpoint to the queue
- Adds the functionality to the worker
- Adds the failover command to the producer
- Adds a failover controller so
/lodabalancer/123/failover will initiate
a failover and return 202
- Adds logic to insert the server group into the
failover flow
Change-Id: Ic4698066773828ae37b55a8d79bd2df6fc6624be
