Use sys.stdlib_module_names?

[wimglenn]

In Python-3.10+ there is sys.stdlib_module_names which might be useful for this app.

There are currently some discrepancies:

>>> from isort.stdlibs.py310 import stdlib
>>> from sys import stdlib_module_names
>>> len(stdlib ^ stdlib_module_names)
94

[anirudnits]

@wimglenn Thanks for pointing this out! I'll surely have a look.