add the files from `handle_distdir` to Dist::Zilla

Make sure that Dist::Zilla knows about all the files created by
`Inline::Module` so that it can package them in the generated tarball.
This is to address the issue at <https://github.com/ingydotnet/dist-zilla-plugin-inlinemodule-pm/issues/5>.

- This requires merging <https://github.com/ingydotnet/inline-module-pm/pull/14> into `Inline::Module`.
- This supersedes PR <https://github.com/ingydotnet/dist-zilla-plugin-inlinemodule-pm/pull/6>.