Userland: Convert TLS::TLSv12 to a Core::Stream::Socket

This commit converts TLS::TLSv12 to a Core::Stream object, and in the
process allows TLS to now wrap other Core::Stream::Socket objects.
As a large part of LibHTTP and LibGemini depend on LibTLS's interface,
this also converts those to support Core::Stream, which leads to a
simplification of LibHTTP (as there's no need to care about the
underlying socket type anymore).
Note that RequestServer now controls the TLS socket options, which is a
better place anyway, as RS is the first receiver of the user-requested
options (though this is currently not particularly useful).

Userland/Libraries/LibHTTP/Forward.h

@@ -10,7 +10,6 @@ namespace HTTP {
 
 class HttpRequest;
 class HttpResponse;
-class HttpJob;
 class HttpsJob;
 class Job;