maint: Use flake8 config file

[s-martin]

• Migrate the settings in GitHub Action to flake file
• Fix flake8 warnings

[coveralls]

Pull Request Test Coverage Report for Build 9054301468

Details

• 1 of 3 (33.33%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.04%) to 78.51%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
components/gpio_control/function_calls.py	0	2	0.0%

Totals
Change from base Build 9049712726:	-0.04%
Covered Lines:	453
Relevant Lines:	577

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💛 - Coveralls