tools.kata-webhook: Specify runtime class using configMap

The kata webhook requires a configmap to define what runtime class it
should set for the newly created pods. Additionally, the configmap
allows others to modify the default runtime class name we wish to set
(in case the handler is kata but the name of the runtimeclass is
different).

Finally, this PR changes the webhook-check to compare the runtime of the
newly created pod against the specific runtime class in the configmap,
if said confimap doesn't exist, then it will default to "kata".

Signed-off-by: Martin <mheberling@microsoft.com>

tools/testing/kata-webhook/deploy/webhook.yaml

@@ -67,3 +67,10 @@ spec:
     targetPort: 8080
   selector:
     app: pod-annotate-webhook
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: kata-webhook
+data:
+  runtime_class: kata

tools/testing/kata-webhook/webhook-check.sh

@@ -16,7 +16,7 @@ source "${webhook_dir}/common.bash"
 
 readonly hello_pod="hello-kata-webhook"
 # The Pod RuntimeClassName for Kata Containers.
-RUNTIME_CLASS="${RUNTIME_CLASS:-"kata"}"
+RUNTIME_CLASS="${RUNTIME_CLASS:-$(kubectl get configmap kata-webhook -o jsonpath='{.data.runtime_class}' 2>/dev/null || echo "kata")}"
 
 cleanup() {
 	{