Add reference to istio to the containers section

[DinisCruz]

As a reference to the next level of containers , and the kind of extra capabilities that are needed (namely on routing and security)

https://istio.io/docs/concepts/traffic-management/

https://github.com/DinisCruz/Book_Generation_Z_Developer/blob/be7614d4db731455d70934c1358b2d1ffa2ca3d6/content/2.mvp-for-gen-z-dev/content/docker.md