Allow specifying additional directories for Python linting

[cowlingjosh]

Often projects contain an examples/ or bin/ directory which contains Python source code, but by default Kraken only lints against source code in src and tests directories.

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This MR adds the ability to specify any number of extra directories for which lint tasks (black, flake8, isort, mypy, pycln, pylint) should also be run against. This functionality is exposed via the python_settings function which modifies the global PythonSettings object.

[ntrinquier]

@cowlingjosh is this still relevant?

[cowlingjosh]

@cowlingjosh is this still relevant?

Apologies for the late reply on this @ntrinquier, I missed the email notifications from Github 🤦 Thanks for the review, I have added your suggestions.

[ntrinquier]

@cowlingjosh one last small comment, let me know what you think!

[cowlingjosh]

@ntrinquier thanks again for the suggestions, I have made the changes.

I have made two other changes as well:

• Updated the poetry.lock file of the kraken-wrapper subproject after the recent ^0.31.0 version bump.
• Changed the log level of the directory does not exist statements to DEBUG, as most likely we want some defaults (such as examples/ etc.) and do not want to overload the output for when these directories do not exist (which will be often).