Stomp.py

* Change code to use cryptography lib rather than PyOpenSSL (which is not recommended for use any more - discussed here: https://github.com/jasonrbriggs/stomp.py/issues/378)

* Add support for backwards compatible CONNECT in 1.1 and 1.2 protocols (https://github.com/jasonrbriggs/stomp.py/pull/348)
* Flip DEFAULT_SSL_VERSION to use ssl.PROTOCOL_TLS rather than ssl.PROTOCOL_TLSv1
* Check SSL certificate for expiry if PyOpenSSL is installed
* Remove deprecated constructor params (use_ssl, and other ssl params)
* Minor cleanup (remove debian packaging config, since it didn't work any more)
* Add log_to_stdout method to force command line logging to stdout (useful for testing)
* Various updates for docker testing
* Add mac keepalive functionality
* Minor update to daemon attribute (https://github.com/jasonrbriggs/stomp.py/pull/361)
* Fix issue with heartbeat listener disconnecting the socket (https://github.com/jasonrbriggs/stomp.py/issues/219 - https://github.com/jasonrbriggs/stomp.py/pull/369)

* Add host bind port patch (https://github.com/jasonrbriggs/stomp.py/issues/331)
* Tidy up based on pycharm suggestions
* Change quotes to be consistent (" rather than ')

* Remove traceback logging (https://github.com/jasonrbriggs/stomp.py/pull/290)
* Add support for \r\n EOL handling (as per [stomp protocol v1.2](http://stomp.github.io/stomp-specification-1.2.html#Augmented_BNF))
* Remove heartbeat loop sleep (issue https://github.com/jasonrbriggs/stomp.py/issues/297, https://github.com/jasonrbriggs/stomp.py/pull/298)
* Update version number using the makefile and the poetry version command
* Add `original_headers` access to the Frame so that you can get the original value of a header even if a listener modifies it (issue: https://github.com/jasonrbriggs/stomp.py/issues/300, PR https://github.com/jasonrbriggs/stomp.py/pull/309)
* Fix for reconnect failures (https://github.com/jasonrbriggs/stomp.py/pull/295)
* Fix for double disconnect notifications causing issues with reconnection
* Add 'verbose' to stomp.logging (and defaulting the value to False). Log lines which dump the stacktrace now use that variable - except for a couple of cases (set stomp.logging.verbose = True to change back to the previous behaviour)

* Update to not allow a null (None) listener when calling set_listener
* Change get_ssl call in connect to be consistent with transport method
* Add a sleep to the heartbeat loop
* Minor change to make quote-use more consistent (replace single with double in most places)
* Change build to use [Python Poetry](https://python-poetry.org/)
* Test coverage improvement
* Threading fix (is_alive) - https://github.com/jasonrbriggs/stomp.py/issues/286