Use overload to type get_global_option

[DanielNoord]

• Add yourself to CONTRIBUTORS if you are a new contributor.
• Write a good description on what the PR does.

Type of Changes

	Type
✓	🔨 Refactoring

Description

The next step in splitting #4954 in more manageable PR's.

I opted to go for overload as it allows us to immediately tell what get_global_option will return or throw an error if it is unspecified.
The globals added to pylint/utils/utils.py could go in pylint/typing but since they won't be used outside of this file I thought it would be best to add them here.

Sorry for making a second PR. The fix turned out to be much easier than anticipated.

[coveralls]

Pull Request Test Coverage Report for Build 1212335532

• 15 of 15 (100.0%) changed or added relevant lines in 3 files are covered.
• 40 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.01%) to 93.112%

---

Files with Coverage Reduction	New Missed Lines	%
pylint/checkers/similar.py	6	96.58%
pylint/checkers/classes.py	34	94.75%

Totals
Change from base Build 1206663671:	0.01%
Covered Lines:	13248
Relevant Lines:	14228

---

💛 - Coveralls

[cdce8p]

I like this a lot 😍

I also though of overload. That was the reason I wanted a separate PR for it 😉
Furthermore the change is quite concise which makes it really easy to review.

[DanielNoord]

Not really sure about the naming of the type alias and TypeVar. Went with GLOBAL_OPTION_NAMES and GLOBAL_OPTION_RETURN_TYPES respectively, but let me know what you think!

[cdce8p]

The TypeVar seems to work. It will prevent things like this where the return type doesn't match the default:

@overload
def get_global_option(
    checker: "BaseChecker", option: GLOBAL_OPTION_BOOL, default: Optional[bool] = None
) -> str:
    ...

[cdce8p]

Looks good! Thanks @DanielNoord 🎉