Porterise existing deployment code

[itowlson]

We have identified a key workflow as "I already have { a Terraform script for AKS / a Helm chart for nginx ingress / a k8s manifest for Consul }, I just want to shove it into my bundle" -> "it produces this output, I want to grab that and pass it to the next step". That is, we do not start from "I want to write a porter.yaml" but from "I have some deployment code, I want to Porterise it."

This implies we should be able to point to existing deployment code and say "add this to my porter.yaml" and to point to outputs (somehow identified) in said code and say "make this visible to Porter."

cc @carolynvs to help make the vision more concrete

[squillace]

@carolynvs @itowlson I think there's a possibility that a mixin/vs code extension should be able to recognize porter.yaml and search for, find, parse, and pre-load creds/params?