Extend usage of import-linter #649
Description
Summary
In #645 , we started to use the import-linter to ensure that imports are restricted to what is within the exasol-toolbox package. We should extend this and ensure that the noxconfig.py is only imported in the exasol.toolbox.nox directory.
This will involve activating such a check for the sub-modules as well as refactoring any affected code to use, i.e. parameters, instead of importing the PROJECT_CONFIG.