jsonnet: add general rules for up/down targets

jsonnet/kube-prometheus/rules/general.libsonnet

@@ -0,0 +1,19 @@
+{
+  prometheusRules+:: {
+    groups+: [
+      {
+        name: 'kube-prometheus-general.rules',
+        rules: [
+          {
+            expr: 'count without(instance, pod, node) (up == 1)',
+            record: 'count:up1',
+          },
+          {
+            expr: 'count without(instance, pod, node) (up == 0)',
+            record: 'count:up0',
+          },
+        ],
+      },
+    ],
+  },
+}

jsonnet/kube-prometheus/rules/rules.libsonnet

@@ -1 +1,2 @@
-(import 'node-rules.libsonnet')
+(import 'node-rules.libsonnet') +
+(import 'general.libsonnet')