Create the write record layer method and object and use it

Create the write record layer method and object and use it

Make sure we set the write record layer method and create the object
where appropriate. Move the newly restructured writing code into the
record layer object.

For now we are cheating and still accessing the underlying SSL_CONNECTION
object. This will be removed in subsequent commits.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19198)