Port HMAC implementation to new OpenSSL APIs

[zooba]

Feature or enhancement

Our current OpenSSL implementation of HMAC is based on the deprecated HMAC API.

We should migrate to the new EVP_MAC-HMAC API instead.

Linked PRs

• gh-134531: cleanup _hashopenssl.c to support EVP_MAC #134626
• [3.14] gh-134531: cleanup _hashopenssl.c to support EVP_MAC (GH-134626) #134703

[picnixz]

I can take care of this. Note that EVP_MAC-HMAC is only available since OpenSSL 3.x and the requirements for CPython are OpenSSL 1.1.1 and later. We still need to maintain the old API (though, we're already doing it through PY_EVP_MD macros) since our build requirements OpenSSL 3.0.9 is the recommended minimum version for the ssl and hashlib extension modules.

[picnixz]

Ok, so I had a quick look at how I would plan this. I'll need multiple PRs because _hashopenssl is a bit messy and now that we will use EVP_MAC in addition to EVP_MD, we should rename some functions. To that end, I'll first make a "cleanup" PR which prepares everything and a bit of refactoring especially to reuse functions later.

Note: I eventually decided against the backports, even if they could ease the life of my future self (see #134626 (comment) and #134703 (comment)).