Provide a local definition of user32.setTimer, user32.KillTimer and ole32.CoGetApartmentType on Windows

[bramd]

By overriding the type definition of SetTimer, we prevent None being passed as the callback parameter. This causes problems when integrating Bleak in larger Windows applications that call SetTimer in this way.

By defining the function type definition locally, we don't override the global definition so existing code that uses None as a callback keeps working.

Pull Request Guidelines for Bleak

Before you submit a pull request, check that it meets these guidelines:

1. If the pull request adds functionality, the docs should be updated.
2. Modify the CHANGELOG.rst, describing your changes as is specified by the
   guidelines in that document.
3. The pull request should work for Python 3.8+ on the following platforms:
   • Windows 10, version 16299 (Fall Creators Update) and greater
   • Linux distributions with BlueZ >= 5.43
   • OS X / macOS >= 10.11
4. Squash all your commits on your PR branch, if the commits are not solving
   different problems and you are committing them in the same PR. In that case,
   consider making several PRs instead.
5. Feel free to add your name as a contributor to the AUTHORS.rst file!

[dlech]

Thanks for the PR! I agree that since Bleak is a library, it shouldn't be modifying Python globals like this. We should fix the other functions as well.

[bramd]

@dlech Good idea to do the other functions as well. I've updated the PR to do this and also made sure to run black this time.

[dlech]

Thanks for updating!

Could you add CHANGELOG entry too?