Add plugins to flake8

[katridi]

check importing order according PEP8 and other recommendations such as:

• [x] flake8-import-order
• [x] flake8-blind-except
• [x] flake8-builtins
• [x] flake8-docstrings
• [x] flake8-quotes
• [x] flake8-eradicate
• [x] flake8-print
• [x] flake8-mutable
• [x] flake8-spellcheck
• [x] pep8-naming