Fix evaluation of NewerNoncurrentVersions (#21096)

- Move VersionPurgeStatus into replication package
- ilm: Evaluate policy w/ obj retention/replication
- lifecycle: Use Evaluator to enforce ILM in scanner
- Unit tests covering ILM, replication and retention
- Simplify NewEvaluator constructor

cmd/data-scanner-metric.go

@@ -104,6 +104,22 @@ func (p *scannerMetrics) log(s scannerMetric, paths ...string) func(custom map[s
 	}
 }
 
+// time n scanner actions.
+// Use for s < scannerMetricLastRealtime
+func (p *scannerMetrics) timeN(s scannerMetric) func(n int) func() {
+	startTime := time.Now()
+	return func(n int) func() {
+		return func() {
+			duration := time.Since(startTime)
+
+			atomic.AddUint64(&p.operations[s], uint64(n))
+			if s < scannerMetricLastRealtime {
+				p.latency[s].add(duration)
+			}
+		}
+	}
+}
+
 // time a scanner action.
 // Use for s < scannerMetricLastRealtime
 func (p *scannerMetrics) time(s scannerMetric) func() {