Add example interval aggregation to MetricRouter config for CI

.github/ci-router.json

@@ -18,5 +18,20 @@
       "if": "*"
     }
   ],
+  "interval_aggregates": [
+    {
+      "name": "temp_cores_avg",
+      "function": "avg(values)",
+      "if": "match('temp_core_%d+', metric.Name())",
+      "tags": {
+        "type": "node"
+      },
+      "meta": {
+        "group": "<copy>",
+        "unit": "<copy>",
+        "source": "MetricAggregator"
+      }
+    }
+  ],
   "interval_timestamp": true
 }