New rule prohibiting modification of `sys.path`

[vraintanakarei]

Description

I think modification of sys.path is a bad practice because it breaks type checking, code completion, code highlighting, etc.
Therefore, I would like to ban it in my team, but I could not find a rule to check it.

If such a rule does not already exist, please consider adding a rule prohibiting changes to sys.path.
For my purpose, these codes should be prohibited with a few exceptions.

• sys.path.append(...)
• sys.path.extend(...)
• sys.path = ...
• etc.

Thank you very much.

[MichaReiser]

This seems reasonable, although I'd prefer to wait to add it until #1774 is complete because we should then have a good place for "restriction" rules -- rules that disallow a valid code pattern mainly because "We don't like it for reasons"