Allow for hash digest encoding type [serde]

[TokenManiac]

Allow an option to specify the encoding type for serde.hash output.

This would be quite convenient, as I often find myself needing the base64-encoded result of hashes to verify file integrity and share it with other online services, such as Roblox’s OpenCloud.

If the argument is left empty, it should default to hex encoding (for backwards compatibility with older versions) or the buffer type, which makes more sense to use.