Be able to accept byte input for Secret & Salt

[Stentonian]

Currently only strings are supported, but we should be able to accept raw bytes.

CLI would need to have some changes. The config & secrets file should be able to have a bytes option. DapolConfigBuilder should also have a bytes option.

Maybe we can get away with simply doing literals, like "\x52" https://doc.rust-lang.org/reference/tokens.html#byte-literals