DerivationFrameworkTop: enable flake8 and make code compliant

...DerivationFramework/DerivationFrameworkTop/CMakeLists.txt

...Framework/DerivationFrameworkTop/python/TOPQCommonJets.py

...work/DerivationFrameworkTop/python/TOPQCommonSelection.py

...ework/DerivationFrameworkTop/python/TOPQCommonSlimming.py

...ework/DerivationFrameworkTop/python/TOPQCommonThinning.py

...ork/DerivationFrameworkTop/python/TOPQCommonTruthTools.py