Kubernetes Autodiscovery Improvements

[andresrc]

Meta issue to group the different fixes and enhancements to make in k8s autodiscovery

• Kubernetes Global Autodiscover (Add option for global kubernetes autodiscover #10578)
• Add JSON options to hints (Add JSON options to hints #12634)
• Move away from kubelet stats/summary (Move away from kubelet stats/summary #12792)
• [ ] Add single state-metrics metricset ([Metricbeat]Create kube-state-metrics metricset which includes all info #12938)
• Make kubernetes autodiscover and metadata work for other resources (Make kubernetes autodiscover and metadata work for other resources #14044)
• Add namespace labels to kubernetes metadata (Add namespace labels to kubernetes metadata #13873)

[exekias]

@odacremolbap I'm closing this one as #12792 wasn't finally scheduled as part of this effort (as kubernetes 1.18 is not out yet). I guess we will push for that one once 1.18 is out