Remove black and add flake8 plugins instead

[iKintosh]

🚀 Feature Request

Motivation

Black does not comply with PEP (PyCQA/pycodestyle#373, psf/black#315)
Flake8 plugins could be tuned as we wish and does make developers pay more attention to code style.

Proposal

Remove black.
Add following plugins:

• https://github.com/m-burst/flake8-pytest-style

• https://github.com/MartinThoma/flake8-simplify

• https://github.com/PyCQA/flake8-commas

• https://github.com/adamchainz/flake8-comprehensions

• https://github.com/PyCQA/flake8-bugbear

• https://github.com/wemake-services/flake8-eradicate

• https://github.com/wemake-services/flake8-broken-line

• https://github.com/afonasev/flake8-return

• https://github.com/best-doctor/flake8-class-attributes-order

• https://github.com/sco1/flake8-annotations (only ANN301)

Test cases

No need

Alternatives

Keep as is

Checklist

• feature proposal description
• motivation
• extra proposal context / proposal alternatives review

[Mr-Geekman]

There are comments in Black's documentation about E203.

[iKintosh]

https://github.com/catalyst-team/codestyle#catalystcodestyle

[Mr-Geekman]

For checking NumPy codestyle:

• pylint.extensions.docparams;
• darglint — can be configured to work with flake8.