[New Rule] Cross-Platform Dev for Python Rules

[Aegrah]

Description

Adding this issue here to add cross-platform compatibility to the following two rules:

• [New Rule] Python Path File (pth) Creation #4499
• [New Rule] Python Site or User Customize File Creation #4500

For these rules, all paths related to PTH loading and sitecustomize.py/usercustomize.py files should be identified for macOS and Windows.