Add tests to check & document behavior of various ways to handle secrets in builds#727

rchincha merged 2 commits intoproject-stacker:mainproject-stacker/stacker:mainfrom

mikemccracken:2025.09.30/main/test-cred-hidingmikemccracken/stacker:2025.09.30/main/test-cred-hidingCopy head branch name to clipboard