Operation request: Twofish implementation

Hi, maybe you consider adding **Twofish** as encryption/decryption operation?

https://en.wikipedia.org/wiki/Twofish

I today needed to investigate some decryption and found that my beloved CyberChef tool does not support Twofish :-(

The issue names no files, tests, or entry points. Start by reviewing the linked Twofish reference and clarifying the required encryption/decryption options and operation behavior. Done would mean an agreed implementation scope and corresponding validation, but the issue does not define either.

Written by the indexing model from the issue text.