review `std/crypto` and `std/hash`

Continuing the discussion from #2719, std/hash shouldn’t be fully deprecated due to its desired streaming functionality that isn’t yet available as a web spec. Although, it’s planned to one day be.

However, std/hash does overlap with std/crypto in a few ways. I have a few suggestions that I think would prune some of this overlapped functionality:

1. Move stream-based functionality within std/hash to std/crypto/streams.
2. Deprecate APIs within std/hash that exist within std/crypto.
3. Move some Hasher methods such as toString as pure functions in std/crypto.

Put simply; I suggest we merge std/hash into std/crypto. Doing so would get rid of duplicate code and maintain streaming support. @kt3k and @cjihrig, what do you guys think?

[cjihrig]

If we can make std/hash completely redundant, I’d be supportive of moving things into std/crypto. If we can’t make it redundant, maybe we should just wait on streaming webcrypto.

[iuioiua]

@kt3k, I’ll go ahead and remove std/hash if and once the above PRs are merged, seeing as it’s been deprecated for a while now.