refactor: use black, flake8 and precommit

[yungbender]

I left the flake8 to be less stricter than new black setup, because otherwise the pipeline would fail with many errors (length of line errors), will make flake8 strict equal to black when we run all files with black.

Secure Coding Practices Checklist GitHub Link

• https://github.com/RedHatInsights/secure-coding-checklist

Secure Coding Checklist

• Input Validation
• Output Encoding
• Authentication and Password Management
• Session Management
• Access Control
• Cryptographic Practices
• Error Handling and Logging
• Data Protection
• Communication Security
• System Configuration
• Database Security
• File Management
• Memory Management
• General Coding Practices

[jira-linking]

Referenced Jiras:
https://issues.redhat.com/browse/VULN-2714

[codecov-commenter]

Codecov Report

Patch coverage: 22.78% and no project coverage change.

Comparison is base (d58ce5a) 67.38% compared to head (03719df) 67.38%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1395   +/-   ##
=======================================
  Coverage   67.38%   67.38%           
=======================================
  Files          53       53           
  Lines        4998     4998           
=======================================
  Hits         3368     3368           
  Misses       1630     1630           

Impacted Files	Coverage Δ
evaluator/evaluator.py	0.00% <0.00%> (ø)
evaluator/logic.py	0.00% <0.00%> (ø)
evaluator/processor.py	0.00% <0.00%> (ø)
listener/advisor_processor.py	0.00% <0.00%> (ø)
listener/inventory_processor.py	0.00% <0.00%> (ø)
listener/listener.py	0.00% <0.00%> (ø)
evaluator/common.py	100.00% <100.00%> (ø)
manager/filters.py	93.54% <100.00%> (ø)

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[mtclinton]

/retest

[yungbender]

/retest

[yungbender]

@psegedy @jdobes My fellow mac friends, could you check in your spare time on this and test it on your machines, if it also works there? thanks

[psegedy]

Please run pre-commit run --all in gh action to force its usage and add to readme that everyone should setup pre-commit in their virtualenv. Something like:

## Setup pre-commit
cd vulnerability-engine
pipenv install --dev
pipenv shell
pre-commit install