The `spring-cloud-kubernetes-commons` module has a compile dependency on `spring-cloud-loadbalancer` which should probably be optional

[mzeijen]

I propose that the spring-cloud-loadbalancer dependency is made optional within thespring-cloud-kubernetes-commons module.

I noticed, using Spring Cloud 2.0.1 but its also in the current 2.0.3-SNAPSHOT version, that thespring-cloud-kubernetes-commons module has a compile dependency on spring-cloud-loadbalancer. This causes Spring Cloud Loadbalancer to be initialised within my applications even though I don't use it. Looking at the code I don't see a reason why the spring-cloud-loadbalancer must be a mandatory dependency. Also, when a user wants to use the Spring Cloud Loadbalancer features within Spring Cloud Kubernetes, a user will need to have a dependency on the spring-cloud-starter-kubernetes-client-loadbalancer or spring-cloud-kubernetes-fabric8-loadbalancer and those modules also already have a dependency on spring-cloud-starter-loadbalancer, so they will get the spring-cloud-starter-loadbalancer dependency as a transitive dependency from those modules. That is why I think that the spring-cloud-loadbalancer dependency is made optional within thespring-cloud-kubernetes-commons module.