CR 6 - remove ctx.Done from go routines and simplify the main function

Author: weilerN

pkg/autoscaler/metricsclient/prometheus.go

@@ -127,7 +127,7 @@ func (pc *PrometheusMetricsClient) getResourceMetrics(ctx context.Context, metri
 	for metricName, queryTemplate := range pc.queryTemplates {
 		windowSizeToResources := metricToWindowSizes[metricName]
 
-		// maximum goroutines is limited to the number of unique windowSize values across all metrics (6 by default).
+		// maximum goroutines is limited to the number of unique windowSize values across all metrics (5 by default).
 		for windowSize, resourcesInWindowSize := range windowSizeToResources {
 			wg.Add(1)
 			go func(resourcesInWindowSize map[string]struct{}, metricName, windowSize string, resultChan chan<- *metricResult) {