Add type stubs

[vmartyanov]

I made stub file, but I can't use it in mypy with current directory structure of pefile. I suppose pefile must be in a single directory for stubs work.

I propose to change current directory structure of the package if it won't cause any issues. As soon as it'll be done, I made a pull request with type stubs

[insolor]

Can you create a repository with the stub file, please?