feat(backend): added heuristics metrics builder

backend/pkg/metrics/heuristics/metrics.go

@@ -0,0 +1,22 @@
+package heuristics
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var heuristicsTotalEvents = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Namespace: "heuristics",
+		Name:      "events_total",
+		Help:      "A counter displaying the number of all processed events",
+	},
+	[]string{"type"},
+)
+
+func IncreaseTotalEvents(eventType string) {
+	heuristicsTotalEvents.WithLabelValues(eventType).Inc()
+}
+
+func List() []prometheus.Collector {
+	return []prometheus.Collector{
+		heuristicsTotalEvents,
+	}
+}