application.py contains checks that should be done in cli.py

[pirat89]

In case of another cleanup, would be nice to move all checks of used cli options combinations into the cli.py. E.g.:

    if self.conf.mode and self.conf.select_rules
        log_message(settings.options_not_allowed)
        return ReturnValues.MODE_SELECT_RULES

Maybe some checks are strewn inside other files. But it doesn't make sense to keep them anywhere outside of cli.py.