What does this implement/fix? Explain your changes.

This handles failure to load internal Delegates type due to misconfigured PythonDLL, which used to raise TypeLoadException whose InnerException would give users the details. Unfortunately, some users do not bother to go as far as to look into the InnerException, and instead go straight to GitHub and report "a bug".

This change handles that TypeLoadException and rethrows it as BadPythonDllException in major entry points, which makes looking into InnerException unnecessary, hopefully reducing the number of "bugs"

Checklist

Check all those that are applicable and complete.

• Make sure to include one or more tests for your change
• If an enhancement PR, please create docs and at best an example
• Add yourself to AUTHORS
• Updated the CHANGELOG