Decouple config and argument parsing

[iyehuda]

Description

Enable using config without triggering argparse. Add linting with mypy in order to catch more kinds of bugs (especially usage of not existing properties).

Contribution Guidelines

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Fixed Issues

Resolves #341

"BEFORE" and "AFTER" output

To verify that the change works as desired, please include an output of terminal before and after the changes under headings "BEFORE" and "AFTER".

Contribution checklist

• [X] I have read the Contributing Guidelines.
• [X] The commits refer to an active issue in the repository.
• [X] I have added automated testing to cover this case.

Notes

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