jsonnet: separate mixins into components

jsonnet/kube-prometheus/alertmanager/alertmanager.libsonnet

jsonnet/kube-prometheus/kube-prometheus.libsonnet

...rometheus/kube-state-metrics/kube-state-metrics.libsonnet

jsonnet/kube-prometheus/mixins/monitoring-mixins.libsonnet

...net/kube-prometheus/node-exporter/node-exporter.libsonnet

...metheus/prometheus-operator/prometheus-operator.libsonnet

jsonnet/kube-prometheus/prometheus/prometheus.libsonnet