- Simplify setup.py: remove unneeded features and get rid of deprecation warnings
- Compatibility with Python 3.10: handle `threading.Event.isSet()` deprecation
- Make sure setup.py could run without `six`: move Patroni class and main function to the `__main__.py`. The `__init__.py` will have only a few functions used by the Patroni class and from the setup.py
Functionality provided by that module will be achieved via callbacks.
- fix a typo in aws.py
- fix some mixups of old code and new callbacks in postgresql.py