Reduce log level for transitive libraries in notebook tests

[ckunki]

In the scope of ticket #193 logging was enabled for testing the Jupyter notebooks with level INFO. The current ticket now additionally requests to reduce the log level for lower level libraries, such as luigi and ITDE.

Proposed approach

1. In file notebook_test_utils.py add function

from inspect import cleandoc
def set_log_level_for_libraries(level=logging.WARNING):
    modules = cleandoc(
        """
        traitlets
        luigi-interface
        luigi-interface.PrepareDockerNetworkForTestEnvironment
        luigi-interface.SpawnTestDockerDatabase
        luigi-interface.SpawnTestEnvironmentWithDockerDB
        luigi-interface.WaitForTestDockerDatabase
        """
    ).split()
    _logger.info(
        f"Setting log level to '%s' for modules\n  - %s",
        logging.getLevelName(level),
        "\n  - ".join(modules),
    )
    for m in modules:
        logging.getLogger(m).setLevel(level)

2. In the resp. Notebook tests import and call this function:

from notebook_test_utils import set_log_level_for_libraries
set_log_level_for_libraries()