Remove deprecated code from apptools.logger

The following code has been deprecated for a while and can be removed from [`apptools.logger.logger`](https://github.com/enthought/apptools/blob/58fbef63179917419525fa175a2a8daa96ef33ac/apptools/logger/logger.py#L54-L79). Note that this code has been deprecated since the very first commit on github.