Fixup and refactor root_env_config resolution#985

bpkroth wants to merge 99 commits into

microsoft:mainmicrosoft/MLOS:mainfrom

bpkroth:fixup-refactor/allow-git-repo-root-env-resolution-from-different-dirs-and-restoresbpkroth/MLOS:fixup-refactor/allow-git-repo-root-env-resolution-from-different-dirs-and-restoresCopy head branch name to clipboard