Add timeout within ksaReqHandler

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

goKMS/kms/akms/server/server.go

@@ -2,7 +2,9 @@ package server
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
+	"time"
 
 	"code.fbi.h-da.de/danet/quant/goKMS/kms/event"
 	"github.com/google/uuid"
@@ -82,7 +84,14 @@ func ksaReqHandler(eventBus *event.EventBus, receiver *Receiver, generateAndSend
 			return
 		}
 
-		<-receiverChan
+		select {
+		case <-receiverChan:
+		case <-time.After(20 * time.Second):
+			http.Error(w, fmt.Sprintf("Platform Key exchange failed for RequestID: %s", kmsKeyRequest.RequestID), http.StatusInternalServerError)
+			logrus.Errorf("Platform Key exchange failed for RequestID: %s", kmsKeyRequest.RequestID)
+			return
+		}
+
 		err = generateAndSend(kmsKeyRequest.ReceivingCKMSID, pathId, kmsKeyRequest.RequestID, kmsKeyRequest.KeyProperties.Number)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)