Give real-world examples of kinds of static and dynamic configuration

[lauracowen]

In the intro text of the static and dynamic config sections of this guide, it talks quite abstractly about how you can do it. It would be useful to give real-world examples in the text of when you might do either. For example, I think dynamic config would be required for K8s containers where the host/port details need updating based on the new connection details of a spun up container - is that right? And for static, maybe just being able to manually change the host name before deployment to different envs within the app's lifecycle.

I don't know if they're the best examples so find someone to confirm!