Topic/default/good practice modernisation

Hello,

Like on yams then on logilab-common, this is a modernization of the code base using commonly shared good pratices:

  • fix check-manifest
  • integrate and apply black
  • various fix: python3 port and missing variables
  • integrate flake8 and fix all bugs
  • migrate to pytest
  • fix some depreciation warnings

Kind regards,

Merge request reports