Remove old python script to generate Grafana dashboards

assets/grafana/_grafanalib.py

assets/grafana/deployment.dashboard.py

assets/grafana/generated/.gitignore

assets/grafana/generated/.keep

assets/grafana/kubernetes-capacity-planning.dashboard.py

assets/grafana/kubernetes-cluster-health.dashboard.py

assets/grafana/kubernetes-cluster-status.dashboard.py

assets/grafana/kubernetes-control-plane-status.dashboard.py

assets/grafana/kubernetes-resource-requests.dashboard.py

assets/grafana/nodes.dashboard.py

assets/grafana/pods.dashboard.py

assets/grafana/prometheus-datasource.json

assets/grafana/raw-json-dashboards/etcd-dashboard.json

assets/grafana/statefulset.dashboard.py