`ssl.PROTOCOL_TLS`, `ssl.PROTOCOL_TLSv1_2`, and so on are deprecated

[oittaa]

All supported Python versions have deprecated TLS version specific configurations.

Deprecated since version 3.6: OpenSSL has deprecated all version specific protocols.

Clients should always use: ssl.PROTOCOL_TLS_CLIENT

Servers should always use: ssl.PROTOCOL_TLS_SERVER

https://docs.python.org/dev/library/ssl.html

[oittaa]

I made auth_suite setting optional and it defaults to ssl.PROTOCOL_TLS_SERVER in #720 . You might want to put some kind of deprecation warning that Python will drop support of those older TLS settings at some point and everyone should just use the "secure by default" settings.

I also synced the patches from the propesed Python 3.12 support #707 but as I mentioned in the comments of the pull request, the tests are so complicated that I didn't really have time to figure out how to fix them. However my Synology NAS was able to connect to a server running my patches.