Move the public SIV mode functions from public headers to internal ones

Move the public SIV mode functions from public headers to internal ones

SIV mode is accessible via EVP. There should be no reason to make the low
level SIV functions from the modes directory part of the public API. Since
these functions do not exist in 1.1.1 we are still able to make this change.

This also reduces the list of newly added undocumented symbols from
issue #9095.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9232)