This adds support for ChaCha20-Poly1305 AEAD algorithm so it is possible
to use it in the same way as AES GCM and other AEAD algorithms. This is
available in OpenSSL 1.1.0+.
OCB mode ciphers were already exposed to openssl_encrypt/decrypt,
but misbehaved, because they were not treated as AEAD ciphers.
From that perspective, OCB should be treated the same way as GCM.
In OpenSSL 1.1 the necessary controls were unified under
EVP_CTRL_AEAD_* (and OCB is only supported since OpenSSL 1.1).
Closes GH-6337.
