Better description of Buildscaler’s architecture & examples

[henryprecheur]

From: https://elotl.atlassian.net/wiki/spaces/SA/pages/67534856/Buildscaler+Testing+12-02-2022

We don’t describe or talk about either examples/buildkite/agent-hpa.yaml or examples/buildkite/buildkite-agent-deploy.yaml, for example what they are or what their purpose is. Although one can look at them and figure out it, we ought to describe them. We should also show in some readme deploying these two yamls via kubectl apply -f file -n $NAMESPACE (namespace needs to be removed from the yaml per prior suggestion/comment)