docs(mtls): add example in combination with 'KafkaTopic' and 'KafkaUser'

Signed-off-by: Sebastian Gaiser <sebastiangaiser@users.noreply.github.com>

packaging/examples/mtls/mtls.yaml

@@ -0,0 +1,69 @@
+---
+apiVersion: kafka.strimzi.io/v1beta2
+kind: KafkaTopic
+metadata:
+  name: canary
+  namespace: kafka
+  labels:
+    strimzi.io/cluster: my-cluster
+spec:
+  partitions: 3
+  replicas: 3
+---
+apiVersion: kafka.strimzi.io/v1beta2
+kind: KafkaUser
+metadata:
+  name: strimzi-canary-client
+  namespace: kafka
+  labels:
+    strimzi.io/cluster: my-cluster
+spec:
+  authentication:
+    type: tls
+  authorization:
+    type: simple
+    acls:
+      - resource:
+          type: topic
+          patternType: literal
+          name: canary
+        operations:
+          - Describe
+          - Write
+          - Alter
+          - Read
+        host: "*"
+      - resource:
+          type: group
+          name: strimzi-canary-group
+          patternType: literal
+        operations:
+          - Read
+        host: "*"
+---
+# deployment part for mTLS
+          env:
+            - name: TOPIC
+              value: "canary"
+            - name: CLIENT_ID
+              value: "strimzi-canary-client"
+            - name: CONSUMER_GROUP_ID
+              value: "strimzi-canary-group"
+            - name: TLS_ENABLED
+              value: "true"
+            - name: TLS_CA_CERT
+              valueFrom:
+                secretKeyRef:
+                  # the CA of your cluster - can be your own CA or created by strimzi
+                  name: my-cluster-cluster-ca-cert
+                  key: ca.crt
+            - name: TLS_CLIENT_CERT
+              valueFrom:
+                secretKeyRef:
+                  name: "strimzi-canary-client"
+                  key: user.crt
+            - name: TLS_CLIENT_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: "strimzi-canary-client"
+                  key: user.key