feat: when exporting / building composite model as a folder output, we should have a file to know it is built by winml cli

currently for build, we have build_manifest.json. 

may be we unify to winmlcli_manifest.json

To distinguish from hf folder, so we could load via WinmlAuto class instead of transformer's

Related pr https://github.com/microsoft/winml-cli/pull/1057