This is a better abstraction than passing in specific pieces of the
Service that each of the cloudproviders may or may not need. For
instance, many of the providers don't need a region, yet this is passed
in. Similarly many of the providers want a string IP for the load
balancer, but it passes in a converted net ip. Affinity is unused by
AWS. A provider change may also require adding a new parameter which has
an effect on all other cloud provider implementations.
Further, this will simplify adding provider specific load balancer
options, such as with labels or some other metadata. For example, we
could add labels for configuring the details of an AWS elastic load
balancer, such as idle timeout on connections, whether it is
internal or external, cross-zone load balancing, and so on.
Authors: @chbatey, @jsravn
Previously the servicecontroller would do the delete, but by having the cloudprovider
take that task on, we can later remove it from the servicecontroller, and the
cloudprovider can do something more efficient.
