Normalize input of ignore-paths for all path types

[DanielNoord]

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Type of Changes

	Type
✓	🐛 Bug fix
✓	✨ New feature

Description

This normalises the input to the ignore-paths config option by creating both a Posix and Windows path from the provided regex pattern.
It does so by adding a new validator called _regexp_paths_csv_validator which creates a list of path regexs.

Furthermore, it adds a new overload to get_global_option for List[Pattern[str]] return types, as we did not have that yet.

Closes #5194

[coveralls]

Pull Request Test Coverage Report for Build 1376349524

• 11 of 11 (100.0%) changed or added relevant lines in 3 files are covered.
• 36 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.05%) to 93.295%

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Files with Coverage Reduction	New Missed Lines	%
pylint/checkers/variables.py	36	95.53%

Totals
Change from base Build 1373933286:	0.05%
Covered Lines:	13678
Relevant Lines:	14661

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💛 - Coveralls

[Pierre-Sassoulas]

Good job normalizing this aspect, this is often used in option and using the same mechanism all the time will save us from bugs and duplication.

[Pierre-Sassoulas]

Very nice cleanup !