Two things we need to do to fix build with OpenSSL 3.0:

1. Use EVP_MAC_* functions instead of HMAC_*
   https://www.openssl.org/docs/man3.0/man3/HMAC_CTX_new.html

2. Load the Legacy provider to enable legacy algorithms, such as MD4
   https://wiki.openssl.org/index.php/OpenSSL_3.0#Programming_in_OpenSSL_3.0

Closes #6477

NO_DOC=build fix
NO_TEST=build fix
NO_CHANGELOG=build fix