* k8s: add k8s_kind arg to KubernetesRawModule
Single–kind k8s modules (e.g. k8s_service) do not have a module
parameter called 'kind' and need to pass a static 'kind' on
KubernetesRawModule class creation. Hence this change.
* k8s: make 'validate' and 'wait' mod params optional
Not all k8s modules utilizing KubernetesRawModule will use these.
* k8s_service: new k8s module for handling Services
Mariusz Mazur