Add Kubernetes kafka Recipe - Bicep

Overview of the Resource type and Recipe

Radius.Messaging/kafka only has an Azure recipe today (Event Hubs, via the AKS recipe pack). Create a Kubernetes Recipe in Bicep for provisioning Kafka in-cluster.

Acceptance criteria

1. A Kubernetes Bicep recipe at Messaging/kafka/recipes/kubernetes/bicep/ that provisions Kafka in-cluster (Deployment/StatefulSet + Service; e.g. Bitnami Kafka / Strimzi) and maps topic.
2. Emits the Radius result object with the resource type's outputs.
3. Recipe entry added to the default Kubernetes recipe pack (recipepack/kubernetes/default-recipepack.bicep) and wired into the publish-bicep-recipes workflow matrix.
4. README for Resource type and Recipe; manual testing with test/app.bicep (make test-recipe).

Additional context

Example: Data/postgreSqlDatabases/recipes/kubernetes/bicep/; contribution guide docs/contributing/contributing-resource-types-recipes.md.