Deprecate CGIHTTPRequestHandler

[donBarbos]

why mention the executable function?
it is an internal function for CGIHTTPRequestHandler and it is also undocumented.

if you want to create stubs for all functions that do not start with _ then there is also nobody_uid (another internal function)

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[srittau]

Yes, we generally include all functions not starting with _. One of the reasons is that otherwise those functions get flagged by stubtest. Another reason is that people tend to use these functions, even if they are not documented.

[srittau]

Thanks!