Add Kubernetes integration tests for EasyHAProxy examples

- Introduced a suite of pytest-based integration tests for Kubernetes using `kind`.
- Automated local installation of dependencies (`kind`, `kubectl`, and `helm`) when missing.
- Implemented fixtures for Kubernetes resource management and TLS secrets.
- Added end-to-end tests for HTTP and HTTPS ingress functionality.

examples/kubernetes/.gitignore

@@ -0,0 +1,9 @@
+# kind installation directory
+.kind/
+
+# kubectl config
+kubeconfig
+
+# Test artifacts
+*.log
+service_tls_generated.yml