Overriding security level requirements for single hosts - SSL_CTX_set_security_level missing from bindings

[Ten0]

The following seems to exist:
https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_security_level.html

But does not exist in openssl_sys.

This prevents from tolerating lower security level (https://askubuntu.com/questions/1233186/ubuntu-20-04-how-to-set-lower-ssl-security-level) for a few hosts instead of globally.

[sfackler]

Happy to take a PR adding it!