Scanner-TODO-Block, deletion of variables

Summary

I'm resolving the following "TODO" block from the scanner-sourcecode:

# TODO: the scoped variables should be cleaned up as soon if the variables
    #       are no longer in the current scope. This can be implemented as follows,
    #       but this breaks the test "test_record_structure_generation", because
    #       some debug info is also deleted. This implementation can be used as soon
    #       as the remaining problems with the debug_tree are fixed.
    # Delete the variables that are no longer needed:
    # scoped_names = record_store.get_names_current_scope()
    # for name in scoped_names:
    #     del record_store[name]
    #     del general_store[name]

(scanner.py, lines 329ff)

See my tests in: https://gitlab.indiscale.com/caosdb/src/caosdb-crawler/-/merge_requests/125