ddup hashing and openssl 3.x

[theAeon]

Was looking through the code to see if there was a less computationally expensive way to handle duplicate files (SHA256 is unnecessary IMO, but that's a separate issue/PR) and as it turns out openssl 3.x drops support for the low level interface to hash functions.

Considering openssl 1.1.1 is EOL in under a year, this may be worth looking at. From what I'm reading, the correct functions are in evp.h per https://stackoverflow.com/questions/69806220/advice-needed-for-migration-of-low-level-openssl-api-to-high-level-openssl-apis