[Fixes #42085125] Adds bouncelog.ec logging to the mailcatcher to get the return-path address

Created a 2nd log name bouncelog.ec that the mailcatcher utilizes to act like a production MS server. Modified the mailcatcher to send bounces to this log.  For completeness sake, this merge also fixes a bug #42230043 that I found as it impacted this and subsequent stories and we need the return-path address to get logged versus the sender address.  Also, changed the format to more closely look like the MS bouncelog

https://support.messagesystems.com/docs/web-ref/log_formats.version_3.php#log_formats.bouncelog3 

New and modified spec files for logging.rb and simple_logging.rb. Changed to use stringio for better investigation of the log contents.  Tested myself and added the testing requirements to story for QA.