Enable OpenSSL to load a configuration file using the standard openssl.cnf file.
In this way, we can change the default OpenSSL ENGINE, as well as configure other capabilities.
This aligns memtier benchmark to a similarly added capability in Redis here : redis/redis#8143

By providing this capability to memtier benchmark, we can ensure that memtier benchmark and redis are using the same OpenSSL configuration (e.g. ENGINE) while performing a test.