Make alerting notifcations sync (#6158)

* tech(routines): move the async logic from notification to alerting notifier

* tech(notification): reduce code dupe

* fix(notification): dont touch the response unless its an error

* feat(alerting): make alerting exeuction async but flow sync

* tech(alerting): remove commented code

* tech(alerting): remove unused code

* tech(alerting): fix typo

* tech(alerting): implement Context on EvalContext

* tech(alerting): wait for all alerts to return

* feat(alerting): dont allow alert responses to cancel

* Revert "feat(alerting): dont allow alert responses to cancel"

This reverts commit 324b006c96.

* feat(alerting): give alerts some time to finish before closing down

pkg/api/metrics.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"context"
 	"encoding/json"
 	"net/http"
 
@@ -31,7 +32,7 @@ func QueryMetrics(c *middleware.Context, reqDto dtos.MetricRequest) Response {
 		})
 	}
 
-	resp, err := tsdb.HandleRequest(request)
+	resp, err := tsdb.HandleRequest(context.TODO(), request)
 	if err != nil {
 		return ApiError(500, "Metric request error", err)
 	}