Replace argon2 with argon2_cffi

[msander]

The replacement is a better supported library which also includes salt generation (crypt.mksalt is too short for argon2).

[Murthy582]

Hi @msander, please let me know when we can expect this enhancement. or suggest a way to do this. Thanks.

[msander]

Hi @Murthy582,
This task is not too difficult and should be a good way to dive into the code if you are interested. I would be happy to see a pull request.

For us, this currently has no high priority, since the current solution is working and secure.
If you want to hire me to do it, drop me a mail.