refactor idea: add a tr_sha_hash type

[ckerr]

If we had something like

using tr_sha_hash = std::array<std::byte, 20>;

and used that everywhere -- this touch a lot of files, but it would also simplify a lot of the code that deals with hashes. Right now we memcmp (..., TR_SHA_LENGTH) everywhere and have a lot of signed char* / unsigned char* / void* ambiguity about handles to these hashes.

[ile6695]

It does look like more c++ with std types.
Did you mean SHA_DIGEST_LENGTH? I couldn't find TR_SHA_LENGTH.

[ckerr]

Yes, that's what I meant.

This is mostly done now with tr_sha1_digest_t, but there are still parts of the codebase using hardcoded arrays w/SHA_DIGEST_LENGTH