- refator: add test coverage for TestReadBOSHReleaseManifestsFromTarballs
- feat: add Stemcell method on BOSHReleaseManifest
- fix linter errors
- refactor: use new stemcell utility

this reduces number of templating functions in the kilnfile.
interpolation in the Kilnfile is a mistake and should be factored out

this is to remove circular dependency when we move bosh release tarball functions to cargo

this is easier to read

type any = interface{}