docs: update greetings example service for easier testing

[JamieDanielson]

Which problem is this PR solving?

• Easier testing with greeting services

Short description of the changes

• Use ClusterIP instead of LoadBalancer type in name, message, and year services to get better event telemetry in Honeycomb
• Add simple alpine pod with curl installed to easily shell in and curl another pod from within the cluster, without

How to verify that this has the expected result

You can hit the frontend endpoint from localhost in your console with curl localhost:7777/greeting and you can hit the frontend endpoint from the alpine image with the IP address of the pod, e.g. curl 10.1.5.100:7777/greeting