#376: rework import structure in lbafapp and other files

[tlamonthezie]

Fixes #376

This pull request includes the following related to the rework of the import structure

• Setup lbaf in editable mode (added to the requirements files for pip)
• Make setup working and test :
  • Validation & Corrections for the package setup
  • Addition of a console script (to run the LBAF application directly by typing lbaf in a console)
• Some code quality changes (with the help of Pylint)
• Some development configuration files to help with code quality
• Refactoring
• upgrade acceptance tests and stepper tests to be run also with python 3.9 on the CI
• Update README.md

Also includes changes from #367 following a merge done because of too many conflicts between the 2 branches

[ppebay]

Please rebase with #374

[ppebay]

@tlamonthezie Not sure why but there are still many conflicts even after the rebase

[tlamonthezie]

@tlamonthezie Not sure why but there are still many conflicts even after the rebase

Yes i see there are still conflicts. I dont know why... i will merge develop into the 376 branch again to resolve that asap

[tlamonthezie]

It's linked to the merge of #367 into develop

[ppebay]

@tlamonthezie I have the following problem:

[pppebay@localhost]~/Documents/Git/LB-analysis-framework/src/lbaf/Applications$ python LBAF_app.py --config conf.yaml
Traceback (most recent call last):
  File "LBAF_app.py", line 11, in <module>
    from lbaf import __version__, PROJECT_PATH
ModuleNotFoundError: No module named 'lbaf'

when trying to run the command: python LBAF_app.py --config conf.yaml