Add support for setting a custom TLS Record Layer

Add support for setting a custom TLS Record Layer

This is just an internal API for now. Something like this will be made
public API at some point - but it is likely to be based on the provider
interface rather that a direct setting of a METHOD like we do for now.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19748)