tls: add ability to get cert/peer cert as X509Certificate object

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/37070


Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>